Original Posted By: "coxwelljon"
Well=2C we've been really dead at work so in my spare time I did some guestimating - not estimating - GUESStimating. This is based on what I percieve to have left to do on my Pietenpol and what I believe it will cost. Also based on the hours to date divided by the number of years/months etc=2C I've been working. Cost = $17/per weekHours per week = 2.5Estimated completion March 2018. Guess I should speed up eh?Tom B. ________________________________________________________________________________Subject: Pietenpol-List: lift struts for GN-1 /Pietenpol
Pietenpol-List: lift struts for GN-1 /Pietenpol
Original Posted By: "Donald Lane"
What is the correct size for ROUND lift struts.I know this has been discussed and I have looked back in the archives but reallydid not find an answer to my question?When I purchased my project it came with 2 complete sets of struts. One set whichis round and a set of cub struts that were shortened. At first I was delightedwith the cub struts but the shortening was done right in the middle andthe cut and weld was done perpendicular to the strut rather than on a diagonal.I do not know what the lower ends are like as they are now sealed.There is a big difference in the weight of the 2 sets and I am leaning toward ROUNDstruts with fairings but cannot find a size for this option on either theGN-1 plans or the Pietenpol plans. I could do engineering calculations if needbe, but would rather not re-invent the wheel.Any help out there?--------Jon CoxwellRecycle and preserve the planetRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
What is the correct size for ROUND lift struts.I know this has been discussed and I have looked back in the archives but reallydid not find an answer to my question?When I purchased my project it came with 2 complete sets of struts. One set whichis round and a set of cub struts that were shortened. At first I was delightedwith the cub struts but the shortening was done right in the middle andthe cut and weld was done perpendicular to the strut rather than on a diagonal.I do not know what the lower ends are like as they are now sealed.There is a big difference in the weight of the 2 sets and I am leaning toward ROUNDstruts with fairings but cannot find a size for this option on either theGN-1 plans or the Pietenpol plans. I could do engineering calculations if needbe, but would rather not re-invent the wheel.Any help out there?--------Jon CoxwellRecycle and preserve the planetRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Re: Pietenpol-List: lift struts for GN-1 /Pietenpol
Original Posted By: "coxwelljon"
You may have to do the math Jon. I looked in the 1932 flying manual and the piet plans there called for streamline strut material.Bryan GreenElgin SC----- Original Message -----
You may have to do the math Jon. I looked in the 1932 flying manual and the piet plans there called for streamline strut material.Bryan GreenElgin SC----- Original Message -----
Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: TOM MICHELLE BRANT
Thanks Bryan,I was afraid of that. I hope I can apply some of my architectural structures toaeronautical engineering. I was hoping that since there are some airplanesflying around with wooden struts that someone may have already done the calculations.--------Jon CoxwellRecycle and preserve the planetRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Thanks Bryan,I was afraid of that. I hope I can apply some of my architectural structures toaeronautical engineering. I was hoping that since there are some airplanesflying around with wooden struts that someone may have already done the calculations.--------Jon CoxwellRecycle and preserve the planetRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Wayne Bressler
Jon,There was a bit of discussion about tbs over on the Tailwind group on yahoo. I think ASS has a conversion in their catalog. I will try to look up the details for you if I can dig it up. I've already deleted those emails.Wayne Bressler Jr.Taildraggers, Inc.taildraggersinc.comSent from the phone that made the Blackberry obsolete.On Oct 18, 2009, at 12:30 AM, "coxwelljon" wrote:> >>> Thanks Bryan,>> I was afraid of that. I hope I can apply some of my architectural > structures to aeronautical engineering. I was hoping that since > there are some airplanes flying around with wooden struts that > someone may have already done the calculations.>> --------> Jon Coxwell> Recycle and preserve the planet>>> Read this topic online here:>> http://forums.matronics.com/viewtopic.p ... __________
Jon,There was a bit of discussion about tbs over on the Tailwind group on yahoo. I think ASS has a conversion in their catalog. I will try to look up the details for you if I can dig it up. I've already deleted those emails.Wayne Bressler Jr.Taildraggers, Inc.taildraggersinc.comSent from the phone that made the Blackberry obsolete.On Oct 18, 2009, at 12:30 AM, "coxwelljon" wrote:> >>> Thanks Bryan,>> I was afraid of that. I hope I can apply some of my architectural > structures to aeronautical engineering. I was hoping that since > there are some airplanes flying around with wooden struts that > someone may have already done the calculations.>> --------> Jon Coxwell> Recycle and preserve the planet>>> Read this topic online here:>> http://forums.matronics.com/viewtopic.p ... __________
Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Owen Davies
Disregarding buckling strength and related issues.....As a point of reference. 1" OD 4130 normalized tubing with .049 wall has a sectionalarea of .149 sq. inches. Per Wicks 4130 link....the normalized tubing hasa tensile strength of 95,000psi. Do the math and you get 14,155 pounds pullper strut.--------PAPA MIKERead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Mon, 19 Oct 2009 14:22:35 -0400
Disregarding buckling strength and related issues.....As a point of reference. 1" OD 4130 normalized tubing with .049 wall has a sectionalarea of .149 sq. inches. Per Wicks 4130 link....the normalized tubing hasa tensile strength of 95,000psi. Do the math and you get 14,155 pounds pullper strut.--------PAPA MIKERead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Mon, 19 Oct 2009 14:22:35 -0400
Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: "coxwelljon"
Guys,As a Consulting Mechanical Engineer, I'm going to jump in here, and make a fewobservations, as not all of us have the same background.When a stressed member is being discussed, it might be helpful to add the equationsneeded so anyone can use them in the future. In the case of the struts beingdiscussed, we have several concepts which, although understood by engineersand those really familiar with the issue being discussed, can become confusingand/or confused.First, the Yield Strength of 4130 is somewhat less than the 95,000 psi given. It turns out that 95,000 psi is generally given as the Ultimate Strength of 4130.The Yield Strength, however, defined to be that level of stress at whichpermanent deformation (stretching) takes place, is around 75,000 psi. (When doingstress calculations, most engineers will use the Yield Strength, not theUltimate, or breaking strength. We not only don't want the member to permanentlystretch, we damn sure don't want it to break. ) The equation describing the strength of any member in tension, and a limited amountof cases in compression, is: s = P/A, where s is the Yield Strength, P is the load in pounds, and A isthe cross-sectional area of the member.In the case of the strut in the discussion, we are looking for the load the memberwill carry, so we rearrange the equation, then "plug & chug" to get: P = s x A = 75,000 x .149 = 11,175 pounds.This will work very nicely in the case of a member being loaded in tension. Ifthat member is a slender bar, shaft, tube, etc., however, column buckling equationscome into play. If the member is a strut at an angle.... we must first apply a little Trig to determinethe vector load on the member prior to determining the load carryingcapacity of that member. Hope this helps.--------Tom KreinerRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Guys,As a Consulting Mechanical Engineer, I'm going to jump in here, and make a fewobservations, as not all of us have the same background.When a stressed member is being discussed, it might be helpful to add the equationsneeded so anyone can use them in the future. In the case of the struts beingdiscussed, we have several concepts which, although understood by engineersand those really familiar with the issue being discussed, can become confusingand/or confused.First, the Yield Strength of 4130 is somewhat less than the 95,000 psi given. It turns out that 95,000 psi is generally given as the Ultimate Strength of 4130.The Yield Strength, however, defined to be that level of stress at whichpermanent deformation (stretching) takes place, is around 75,000 psi. (When doingstress calculations, most engineers will use the Yield Strength, not theUltimate, or breaking strength. We not only don't want the member to permanentlystretch, we damn sure don't want it to break. ) The equation describing the strength of any member in tension, and a limited amountof cases in compression, is: s = P/A, where s is the Yield Strength, P is the load in pounds, and A isthe cross-sectional area of the member.In the case of the strut in the discussion, we are looking for the load the memberwill carry, so we rearrange the equation, then "plug & chug" to get: P = s x A = 75,000 x .149 = 11,175 pounds.This will work very nicely in the case of a member being loaded in tension. Ifthat member is a slender bar, shaft, tube, etc., however, column buckling equationscome into play. If the member is a strut at an angle.... we must first apply a little Trig to determinethe vector load on the member prior to determining the load carryingcapacity of that member. Hope this helps.--------Tom KreinerRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Robert Ray
Cliff,Thanks! That makes life a little easier .--------Jon CoxwellRecycle and preserve the planetRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Oct 2009 01:21:20 -0400Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Cliff,Thanks! That makes life a little easier .--------Jon CoxwellRecycle and preserve the planetRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 20 Oct 2009 01:21:20 -0400Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: "Lagowski Morrow"
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolNot being an engineer of any sort type or configuration or disciplines, rocket scientist or mathematician. The explanation is great as is sharing the equation. And knowing the compression factors and or forces is a really nice piece of information. However that assumes one knows or can anticipate the loading, which brings me to my question. How do we determine the loading values or amounts such that we are able to compare design and materials yield based upon a calculated or anticipated need of in flight loading ? Naturally that assumes that the need is the exact amount of stress applied to a particular structural member during full and repeated loading? What are the effects of shape, materials, laminations, composites and metals on their ability to support the load and resistfailure?For me, not being math savvy, are considered complex concepts and calculations that are well beyond my simple math skills and aerodynamic calculationcapabilities. I would like someone to provide a simple but effective way for me and other mathematically challenged builders to determine the efficacy of our material choices and their ability to respond to a range of loadswithout failure?In short we, correction, I speak for those of us that do not have a death wish but are mathematically challenged and of a mature age who just want to fly a safe aircraft, how do we determine those factors pre test flight rather then post or during test flight activities? I suspect that learning about catastrophic material failure during a test flight is not a good thing and may be subject to screwing up ones entire day.JohnIn a message dated 10/20/2009 12:33:26 A.M. Eastern Daylight Time, tkreiner(at)gmail.com writes:--> Pietenpol-List message posted by: "tkreiner" Guys,As a Consulting Mechanical Engineer, I'm going to jump in here, and make a few observations, as not all of us have the same background.When a stressed member is being discussed, it might be helpful to add the equations needed so anyone can use them in the future. In the case of the struts being discussed, we have several concepts which, although understood by engineers and those really familiar with the issue being discussed, can become confusing and/or confused.First, the Yield Strength of 4130 is somewhat less than the 95,000 psi given. It turns out that 95,000 psi is generally given as the Ultimate Strength of 4130. The Yield Strength, however, defined to be that level of stress at which permanent deformation (stretching) takes place, is around 75,000psi. (When doing stress calculations, most engineers will use the Yield Strength, not the Ultimate, or breaking strength. We not only don't want the member to permanently stretch, we damn sure don't want it to break. ) The equation describing the strength of any member in tension, and a limited amount of cases in compression, is:s = P/A, where s is the Yield Strength, P is the load in pounds, and A is the cross-sectional area of the member.In the case of the strut in the discussion, we are looking for the load the member will carry, so we rearrange the equation, then "plug & chug" to get:P = s x A = 75,000 x .149 = 11,175 pounds.This will work very nicely in the case of a member being loaded in tension. If that member is a slender bar, shaft, tube, etc., however, columnbuckling equations come into play. If the member is a strut at an angle.... we must first apply a little Trig to determine the vector load on the member prior to determining the load carrying capacity of that member. Hope this helps.--------Tom KreinerRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolNot being an engineer of any sort type or configuration or disciplines, rocket scientist or mathematician. The explanation is great as is sharing the equation. And knowing the compression factors and or forces is a really nice piece of information. However that assumes one knows or can anticipate the loading, which brings me to my question. How do we determine the loading values or amounts such that we are able to compare design and materials yield based upon a calculated or anticipated need of in flight loading ? Naturally that assumes that the need is the exact amount of stress applied to a particular structural member during full and repeated loading? What are the effects of shape, materials, laminations, composites and metals on their ability to support the load and resistfailure?For me, not being math savvy, are considered complex concepts and calculations that are well beyond my simple math skills and aerodynamic calculationcapabilities. I would like someone to provide a simple but effective way for me and other mathematically challenged builders to determine the efficacy of our material choices and their ability to respond to a range of loadswithout failure?In short we, correction, I speak for those of us that do not have a death wish but are mathematically challenged and of a mature age who just want to fly a safe aircraft, how do we determine those factors pre test flight rather then post or during test flight activities? I suspect that learning about catastrophic material failure during a test flight is not a good thing and may be subject to screwing up ones entire day.JohnIn a message dated 10/20/2009 12:33:26 A.M. Eastern Daylight Time, tkreiner(at)gmail.com writes:--> Pietenpol-List message posted by: "tkreiner" Guys,As a Consulting Mechanical Engineer, I'm going to jump in here, and make a few observations, as not all of us have the same background.When a stressed member is being discussed, it might be helpful to add the equations needed so anyone can use them in the future. In the case of the struts being discussed, we have several concepts which, although understood by engineers and those really familiar with the issue being discussed, can become confusing and/or confused.First, the Yield Strength of 4130 is somewhat less than the 95,000 psi given. It turns out that 95,000 psi is generally given as the Ultimate Strength of 4130. The Yield Strength, however, defined to be that level of stress at which permanent deformation (stretching) takes place, is around 75,000psi. (When doing stress calculations, most engineers will use the Yield Strength, not the Ultimate, or breaking strength. We not only don't want the member to permanently stretch, we damn sure don't want it to break. ) The equation describing the strength of any member in tension, and a limited amount of cases in compression, is:s = P/A, where s is the Yield Strength, P is the load in pounds, and A is the cross-sectional area of the member.In the case of the strut in the discussion, we are looking for the load the member will carry, so we rearrange the equation, then "plug & chug" to get:P = s x A = 75,000 x .149 = 11,175 pounds.This will work very nicely in the case of a member being loaded in tension. If that member is a slender bar, shaft, tube, etc., however, columnbuckling equations come into play. If the member is a strut at an angle.... we must first apply a little Trig to determine the vector load on the member prior to determining the load carrying capacity of that member. Hope this helps.--------Tom KreinerRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Ryan Mueller
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: "Gary Boothe"
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolRyan,Thanks for the info.Actually the question was more to what are the calculations in a simple format. I will spend the time doing them if I knew what to do. Although being an admitted plan deviate offender, motivated,not for money or weight but for style and appearance preferences. I really wasn't asking for someone to do my work for me but rather to point me in the right direction with an equation that I can use myself or with little coaching to makethose calculations for my own theoretical piece of mind.As a safety professional for more than 30 years in the discipline and 15 or so in consulting I have always advocated a simple but effective operational model, " never expect someone else to do what you are not willingto do yourself". The philosophy has served me well and has protected many people from accident, injury, occupational illness and the inadvertent acts or errant and emotionally unstable individuals.But still not an engineer, rocket scientist, mathematical genius or marathon runner, always a good idea to know and live within ones physical and intellectual limitations.John In a message dated 10/20/2009 10:40:41 A.M. Eastern Daylight Time, rmueller23(at)gmail.com writes:John, If one is going to depart from the plans in such a way that most don't, for example with the use of round tubing for wing struts instead of streamlined, then the only way to know for sure which size tubing would be suitableis to figure out the math and perform the calculations. You may save money on materials, but you will have to spend the time to figure out what to substitute. Personally I prefer to save the time and fretting, and just go with the plans, or consult the 80 years of empirical knowledge that have been accumulated about how to build a Piet. The plans work, so that ought to be option#1. If you deviate from the plans either because of the need to address a perceived issue or maybe because materials (such as the streamline tubing Bernard had) are no longer available, and you do not want to have to perform the engineering to know for sure whether your change will work, then you ought to just copy what others have done successfully. Maybe they did the calculations, flew it, and it works. Or maybe they just eyeballed it, flew it,and it still worked. Either way someone else bore the risk of test flying the concept for you. Again, if not wanting to do the calculations yourself, I would think that would be the route to go. For what it's worth... :PHave a good day,RyanOn Tue, Oct 20, 2009 at 8:40 AM, wrote:Not being an engineer of any sort type or configuration or disciplines, rocket scientist or mathematician. The explanation is great as is sharing theequation. And knowing the compression factors and or forces is a really nice piece of information. However that assumes one knows or can anticipate the loading, which brings me to my question. How do we determine the loading values or amounts such that we are able to compare design and materials yield based upon a calculated or anticipated need of in flight loading ? Naturally that assumes that the need is the exact amount of stress applied to a particular structural member during full and repeated loading? What are the effects of shape, materials, laminations, composites and metals on their ability to support the load and resistfailure?For me, not being math savvy, are considered complex concepts and calculations that are well beyond my simple math skills and aerodynamic calculationcapabilities. I would like someone to provide a simple but effective way for me and other mathematically challenged builders to determine the efficacy of our material choices and their ability to respond to a range of loadswithout failure?In short we, correction, I speak for those of us that do not have a death wish but are mathematically challenged and of a mature age who just want to fly a safe aircraft, how do we determine those factors pre test flight rather then post or during test flight activities? I suspect that learning about catastrophic material failure during a test flight is not a good thing and may be subject to screwing up ones entire day.JohnIn a message dated 10/20/2009 12:33:26 A.M. Eastern Daylight Time, _tkreiner(at)gmail.com_ (mailto:tkreiner(at)gmail.com) writes:(mailto:tkreiner(at)gmail.com) >Guys,As a Consulting Mechanical Engineer, I'm going to jump in here, and make a few observations, as not all of us have the same background.When a stressed member is being discussed, it might be helpful to add the equations needed so anyone can use them in the future. In the case of the struts being discussed, we have several concepts which, although understood by engineers and those really familiar with the issue being discussed,can become confusing and/or confused.First, the Yield Strength of 4130 is somewhat less than the 95,000 psi given. It turns out that 95,000 psi is generally given as the Ultimate Strength of 4130. The Yield Strength, however, defined to be that level of stress at which permanent deformation (stretching) takes place, is around 75,000 psi. (When doing stress calculations, most engineers will use the YieldStrength, not the Ultimate, or breaking strength. We not only don't want the member to permanently stretch, we damn sure don't want it to break. ) The equation describing the strength of any member in tension, and a limited amount of cases in compression, is:s = P/A, where s is the Yield Strength, P is the load in pounds, and A is the cross-sectional area of the member.In the case of the strut in the discussion, we are looking for the load the member will carry, so we rearrange the equation, then "plug & chug" to get:P = s x A = 75,000 x .149 = 11,175 pounds.This will work very nicely in the case of a member being loaded in tension. If that member is a slender bar, shaft, tube, etc., however, columnbuckling equations come into play. If the member is a strut at an angle.... we must first apply a little Trig to determine the vector load on the member prior to determining the load carrying capacity of that member. Hope this helps.--------Tom Kreiner Read this topic online here:_http://forums.matronics.com/viewtopic.php?p=268647#268647=====================_ (http://forums.matronics.com/viewtopic.p ... ==========) Use the ties Day ======================= - MATRONICS WEB FORUMS ======================= - List Contribution Web Site sp; " target="_blank">http://www.matronics.com/Navigator?Piet ... ronics.com _blank">http://www.matronics.com/contribution (http://www.matronics.com/Navigator?Pietenpol-List) (http://www.matronics.com/contribution) ________________________________________________________________________________
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolRyan,Thanks for the info.Actually the question was more to what are the calculations in a simple format. I will spend the time doing them if I knew what to do. Although being an admitted plan deviate offender, motivated,not for money or weight but for style and appearance preferences. I really wasn't asking for someone to do my work for me but rather to point me in the right direction with an equation that I can use myself or with little coaching to makethose calculations for my own theoretical piece of mind.As a safety professional for more than 30 years in the discipline and 15 or so in consulting I have always advocated a simple but effective operational model, " never expect someone else to do what you are not willingto do yourself". The philosophy has served me well and has protected many people from accident, injury, occupational illness and the inadvertent acts or errant and emotionally unstable individuals.But still not an engineer, rocket scientist, mathematical genius or marathon runner, always a good idea to know and live within ones physical and intellectual limitations.John In a message dated 10/20/2009 10:40:41 A.M. Eastern Daylight Time, rmueller23(at)gmail.com writes:John, If one is going to depart from the plans in such a way that most don't, for example with the use of round tubing for wing struts instead of streamlined, then the only way to know for sure which size tubing would be suitableis to figure out the math and perform the calculations. You may save money on materials, but you will have to spend the time to figure out what to substitute. Personally I prefer to save the time and fretting, and just go with the plans, or consult the 80 years of empirical knowledge that have been accumulated about how to build a Piet. The plans work, so that ought to be option#1. If you deviate from the plans either because of the need to address a perceived issue or maybe because materials (such as the streamline tubing Bernard had) are no longer available, and you do not want to have to perform the engineering to know for sure whether your change will work, then you ought to just copy what others have done successfully. Maybe they did the calculations, flew it, and it works. Or maybe they just eyeballed it, flew it,and it still worked. Either way someone else bore the risk of test flying the concept for you. Again, if not wanting to do the calculations yourself, I would think that would be the route to go. For what it's worth... :PHave a good day,RyanOn Tue, Oct 20, 2009 at 8:40 AM, wrote:Not being an engineer of any sort type or configuration or disciplines, rocket scientist or mathematician. The explanation is great as is sharing theequation. And knowing the compression factors and or forces is a really nice piece of information. However that assumes one knows or can anticipate the loading, which brings me to my question. How do we determine the loading values or amounts such that we are able to compare design and materials yield based upon a calculated or anticipated need of in flight loading ? Naturally that assumes that the need is the exact amount of stress applied to a particular structural member during full and repeated loading? What are the effects of shape, materials, laminations, composites and metals on their ability to support the load and resistfailure?For me, not being math savvy, are considered complex concepts and calculations that are well beyond my simple math skills and aerodynamic calculationcapabilities. I would like someone to provide a simple but effective way for me and other mathematically challenged builders to determine the efficacy of our material choices and their ability to respond to a range of loadswithout failure?In short we, correction, I speak for those of us that do not have a death wish but are mathematically challenged and of a mature age who just want to fly a safe aircraft, how do we determine those factors pre test flight rather then post or during test flight activities? I suspect that learning about catastrophic material failure during a test flight is not a good thing and may be subject to screwing up ones entire day.JohnIn a message dated 10/20/2009 12:33:26 A.M. Eastern Daylight Time, _tkreiner(at)gmail.com_ (mailto:tkreiner(at)gmail.com) writes:(mailto:tkreiner(at)gmail.com) >Guys,As a Consulting Mechanical Engineer, I'm going to jump in here, and make a few observations, as not all of us have the same background.When a stressed member is being discussed, it might be helpful to add the equations needed so anyone can use them in the future. In the case of the struts being discussed, we have several concepts which, although understood by engineers and those really familiar with the issue being discussed,can become confusing and/or confused.First, the Yield Strength of 4130 is somewhat less than the 95,000 psi given. It turns out that 95,000 psi is generally given as the Ultimate Strength of 4130. The Yield Strength, however, defined to be that level of stress at which permanent deformation (stretching) takes place, is around 75,000 psi. (When doing stress calculations, most engineers will use the YieldStrength, not the Ultimate, or breaking strength. We not only don't want the member to permanently stretch, we damn sure don't want it to break. ) The equation describing the strength of any member in tension, and a limited amount of cases in compression, is:s = P/A, where s is the Yield Strength, P is the load in pounds, and A is the cross-sectional area of the member.In the case of the strut in the discussion, we are looking for the load the member will carry, so we rearrange the equation, then "plug & chug" to get:P = s x A = 75,000 x .149 = 11,175 pounds.This will work very nicely in the case of a member being loaded in tension. If that member is a slender bar, shaft, tube, etc., however, columnbuckling equations come into play. If the member is a strut at an angle.... we must first apply a little Trig to determine the vector load on the member prior to determining the load carrying capacity of that member. Hope this helps.--------Tom Kreiner Read this topic online here:_http://forums.matronics.com/viewtopic.php?p=268647#268647=====================_ (http://forums.matronics.com/viewtopic.p ... ==========) Use the ties Day ======================= - MATRONICS WEB FORUMS ======================= - List Contribution Web Site sp; " target="_blank">http://www.matronics.com/Navigator?Piet ... ronics.com _blank">http://www.matronics.com/contribution (http://www.matronics.com/Navigator?Pietenpol-List) (http://www.matronics.com/contribution) ________________________________________________________________________________
RE: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: owner-pietenpol-list-server(at)matronics.com
John,I'm with you. I am also a "deviate" for the purpose of style and appearance(for my Piet, that is). It would be very nice to have all the math andengineering to back up my ideas (wood cabanes and struts). Clif Dawson sentme some interesting calc's that confirmed that wood cabanes were indeed wellwithin the safe limits. But I know just enough to be dangerous, such as:What are the effects of side-ways loads? Compression? What are thecontributions of the cables to compliment the struts? The latter alonebrings up a whole bunch of other calculations, merely showing that thestruts certainly do not act alone.In the end, I followed Ryan's sage advice and just copied what has shown tobe successful. Too bad I haven't followed that same advice on the financialend. My model is: Buy high.sell cheap! Someday it may pay off - who knows?Gary BootheCool, Ca.PietenpolWW Corvair Conversion, mountedTail done, Fuselage on gear(15 ribs down.) _____
John,I'm with you. I am also a "deviate" for the purpose of style and appearance(for my Piet, that is). It would be very nice to have all the math andengineering to back up my ideas (wood cabanes and struts). Clif Dawson sentme some interesting calc's that confirmed that wood cabanes were indeed wellwithin the safe limits. But I know just enough to be dangerous, such as:What are the effects of side-ways loads? Compression? What are thecontributions of the cables to compliment the struts? The latter alonebrings up a whole bunch of other calculations, merely showing that thestruts certainly do not act alone.In the end, I followed Ryan's sage advice and just copied what has shown tobe successful. Too bad I haven't followed that same advice on the financialend. My model is: Buy high.sell cheap! Someday it may pay off - who knows?Gary BootheCool, Ca.PietenpolWW Corvair Conversion, mountedTail done, Fuselage on gear(15 ribs down.) _____
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolGary,That's the flaw in the logic, its buy high, sell low and make it up in volume!Actually I am using wood for the lift struts, cabanes and landing gear laminated with metal inserts at connection points that are slightly more stout than streamline tubing. There are some of those flying so empirical information may be available I again would like to see how those values are calculated for my own edification and piece of mind. That being said they look great!I have pics of the lift struts and landing gear, not great looking form the pic but impressive in person. The cabanes have stainless tubing embeddedto add metallic strength but also to conceal utilities, plumbing and wiring. got to reduce the drag hide the junk and build a more attractive cleanerpiet.All the exterior wood is being finished by that polyurethane top coat I bought from Rick, wow that stuff is really nice and with a number of coats I suspect it will be bullet proof. My spray technique and paint area is still in need of technique perfection and technological advancements but that again is an in time issue. for the moment I am getting a good coat on the wood to protect of from shop hazards, oils colorants and greasy fingered grandson shop assistants who at the ripe old age of 4.999 years will more then likely insist upon being awarded the repairman's certificate..John In a message dated 10/20/2009 11:43:05 A.M. Eastern Daylight Time, gboothe5(at)comcast.net writes:John, I=99m with you. I am also a =9Cdeviate=9D for the purpose of style and appearance (for my Piet, that is). It would be very nice to have all the math and engineering to back up my ideas (wood cabanes and struts). Clif Dawson sent me some interesting calc=99s that confirmed that wood cabanes were indeed well within the safe limits. But I know just enough to be dangerous, such as: What are the effects of side-ways loads? Compression? What are the contributions of the cables to compliment the struts? The latter alone brings up a whole bunch of other calculations, merely showing that the struts certainly do not act alone. In the end, I followed Ryan=99s sage advice and just copied what has shown to be successful. Too bad I haven=99t followed that same advice on the financial end. My model is: Buy highsell cheap! Someday it may pay off =93 who knows? Gary Boothe Cool, Ca. Pietenpol WW Corvair Conversion, mounted Tail done, Fuselage on gear (15 ribs down)____________________________________
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolGary,That's the flaw in the logic, its buy high, sell low and make it up in volume!Actually I am using wood for the lift struts, cabanes and landing gear laminated with metal inserts at connection points that are slightly more stout than streamline tubing. There are some of those flying so empirical information may be available I again would like to see how those values are calculated for my own edification and piece of mind. That being said they look great!I have pics of the lift struts and landing gear, not great looking form the pic but impressive in person. The cabanes have stainless tubing embeddedto add metallic strength but also to conceal utilities, plumbing and wiring. got to reduce the drag hide the junk and build a more attractive cleanerpiet.All the exterior wood is being finished by that polyurethane top coat I bought from Rick, wow that stuff is really nice and with a number of coats I suspect it will be bullet proof. My spray technique and paint area is still in need of technique perfection and technological advancements but that again is an in time issue. for the moment I am getting a good coat on the wood to protect of from shop hazards, oils colorants and greasy fingered grandson shop assistants who at the ripe old age of 4.999 years will more then likely insist upon being awarded the repairman's certificate..John In a message dated 10/20/2009 11:43:05 A.M. Eastern Daylight Time, gboothe5(at)comcast.net writes:John, I=99m with you. I am also a =9Cdeviate=9D for the purpose of style and appearance (for my Piet, that is). It would be very nice to have all the math and engineering to back up my ideas (wood cabanes and struts). Clif Dawson sent me some interesting calc=99s that confirmed that wood cabanes were indeed well within the safe limits. But I know just enough to be dangerous, such as: What are the effects of side-ways loads? Compression? What are the contributions of the cables to compliment the struts? The latter alone brings up a whole bunch of other calculations, merely showing that the struts certainly do not act alone. In the end, I followed Ryan=99s sage advice and just copied what has shown to be successful. Too bad I haven=99t followed that same advice on the financial end. My model is: Buy highsell cheap! Someday it may pay off =93 who knows? Gary Boothe Cool, Ca. Pietenpol WW Corvair Conversion, mounted Tail done, Fuselage on gear (15 ribs down)____________________________________
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Ryan Mueller
Words of wisdom!David Paule ----- Original Message -----
Words of wisdom!David Paule ----- Original Message -----
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Ken Howe
Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: "Catdesigns"
CDAWSON5854(at)shaw.ca wrote:> ...> I finaly scanned them for you guys strutting about.> ... It was hardly readable for me, so I've run it through my OCR software, here isthe result:---Stress Analysis Made Painlessby Raoul J. HoffmanAeronautical Designing EngineerAirplane members, subjected to axial compression loads, are called posts, columnsor struts.No formula has yet been found which will give you the exact load permissible undervarious conditions. There are two formulas commonly used for strut calculations-- one for short struts and one for long members.Usually, Johnson's parabolic formula is used for short struts and Euler's formulafor long struts. These formulae are based on the assumptions that the strutis straight, of homogenous material and that the load is applied at the centerof gravity of the strut.The formulae shown on the chart are simplified for ready use. (P) denotes the loadpermissible in pounds and (A) the cross-sectional area in square inches. Therefore,P/A will give you the average stress per square inch. (L) denotes thefree length, (r) the radius of gyration. (L/r) the slenderness ratio and (E)the modulus of elasticity.The modulus of elasticity is a constant factor of elongation. taken within theelastic limit and may be expressed as the theoretical load required to elongatea rod to twice the original length, having a cross-sectional area of one squareinch. The elastic limit is the limit of stress within which the deformationor elongation disappears after removing the stress.The area of cross-section is easily found by measuring. We calibrated a specialscale for the weight of a one foot length of steel tubing to use instead of tirearea. (L), the free length. is the unsupported length or the bar between thepoints of inflection, or the points where the curvature of the flexed strutreverses. The free Length of a strut, with pin ends or rounded ends, is equalto the total length of the strut. For a strut with fixed ends (restrained), thefree length would be 50 percent of its actual length, but in airplane workwe should seldom be below 70 percent.The radius of gyration is a factor depending on the outline and area or the strutcross-section. These multiplication constants are noted on the chart for afew standard strut sections. Multiply the outside dimension by the constant andyou will have the radius of gyration. always take the smaller for (r) dimension,specially in case of a rectangular section, except when you are sure thestrut is braced or notable to deflect in the perpendicular direction.The slenderness ratio (L/r) is the ratio of the free length of the strut to theradius of gyration. The selection of the formula depends on the slenderness ratio,which will also determine the average stress per square inch. Both formulaeare valid as long as the ratio of the outside dimension to the wall thicknessdoes not go beyond a certain value.Estimating an engine-mount vie use the total length for the free length, even ifthe ends are restrained at the connections. For fuselage members, we use 70percent to 100 percent for the free length, depending on the judgment of the designer.Do not go beyond a slenderness ratio of 150 for carbon steel nor beyond180 for chrome molybdenum steel which may be subjected to an external load,and not over 200 in case the member is protected from external load.The minimum wall thickness for steel tubing should not be less than .035 in., exceptfor the rear end of a cabin or for fuselage members other than longeronswhere .028 in. tubing can be used. A margin of safety of 50 percent must be maintainedthroughout.Scale No 1 on our chart shows the slenderness ratio for spruce on the lower partand for mild carbon and chrome molybdenum on the upper part, with the correspondingmaximum loads per square inch on scale No. 4.The calibrations for both steels over 130 are the same, involving an error of 3percent, the percentage difference between their respective modulus of elasticity.By following the example you are able to design your own strut by changingthe cross-sectional area of the strut until it can carry the load required.---Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
CDAWSON5854(at)shaw.ca wrote:> ...> I finaly scanned them for you guys strutting about.> ... It was hardly readable for me, so I've run it through my OCR software, here isthe result:---Stress Analysis Made Painlessby Raoul J. HoffmanAeronautical Designing EngineerAirplane members, subjected to axial compression loads, are called posts, columnsor struts.No formula has yet been found which will give you the exact load permissible undervarious conditions. There are two formulas commonly used for strut calculations-- one for short struts and one for long members.Usually, Johnson's parabolic formula is used for short struts and Euler's formulafor long struts. These formulae are based on the assumptions that the strutis straight, of homogenous material and that the load is applied at the centerof gravity of the strut.The formulae shown on the chart are simplified for ready use. (P) denotes the loadpermissible in pounds and (A) the cross-sectional area in square inches. Therefore,P/A will give you the average stress per square inch. (L) denotes thefree length, (r) the radius of gyration. (L/r) the slenderness ratio and (E)the modulus of elasticity.The modulus of elasticity is a constant factor of elongation. taken within theelastic limit and may be expressed as the theoretical load required to elongatea rod to twice the original length, having a cross-sectional area of one squareinch. The elastic limit is the limit of stress within which the deformationor elongation disappears after removing the stress.The area of cross-section is easily found by measuring. We calibrated a specialscale for the weight of a one foot length of steel tubing to use instead of tirearea. (L), the free length. is the unsupported length or the bar between thepoints of inflection, or the points where the curvature of the flexed strutreverses. The free Length of a strut, with pin ends or rounded ends, is equalto the total length of the strut. For a strut with fixed ends (restrained), thefree length would be 50 percent of its actual length, but in airplane workwe should seldom be below 70 percent.The radius of gyration is a factor depending on the outline and area or the strutcross-section. These multiplication constants are noted on the chart for afew standard strut sections. Multiply the outside dimension by the constant andyou will have the radius of gyration. always take the smaller for (r) dimension,specially in case of a rectangular section, except when you are sure thestrut is braced or notable to deflect in the perpendicular direction.The slenderness ratio (L/r) is the ratio of the free length of the strut to theradius of gyration. The selection of the formula depends on the slenderness ratio,which will also determine the average stress per square inch. Both formulaeare valid as long as the ratio of the outside dimension to the wall thicknessdoes not go beyond a certain value.Estimating an engine-mount vie use the total length for the free length, even ifthe ends are restrained at the connections. For fuselage members, we use 70percent to 100 percent for the free length, depending on the judgment of the designer.Do not go beyond a slenderness ratio of 150 for carbon steel nor beyond180 for chrome molybdenum steel which may be subjected to an external load,and not over 200 in case the member is protected from external load.The minimum wall thickness for steel tubing should not be less than .035 in., exceptfor the rear end of a cabin or for fuselage members other than longeronswhere .028 in. tubing can be used. A margin of safety of 50 percent must be maintainedthroughout.Scale No 1 on our chart shows the slenderness ratio for spruce on the lower partand for mild carbon and chrome molybdenum on the upper part, with the correspondingmaximum loads per square inch on scale No. 4.The calibrations for both steels over 130 are the same, involving an error of 3percent, the percentage difference between their respective modulus of elasticity.By following the example you are able to design your own strut by changingthe cross-sectional area of the strut until it can carry the load required.---Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Ken Howe
Uhhh...--------Mark - working on wingsRead this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/say_ ... ___Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolDate: Tue, 20 Oct 2009 14:46:06 -0600
Uhhh...--------Mark - working on wingsRead this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/say_ ... ___Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolDate: Tue, 20 Oct 2009 14:46:06 -0600
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: AMsafetyC(at)aol.com
Hi John, there is no simple equation to tell you the various loads that a strut will see under all flight and landing conditions. However you can get close if you make several assumptions, such as the chord wise load distribution at maximum lift which will determine the difference in loads that the front and rear struts will see. Also the span wise load distribution at maximum lift which will determine the ratio of the load shared between the main struts and the cabane struts. If you have used longer cabane struts and some dihedral the angle of the main struts will be different as will the tension and compression loads they see. Using a different airfoil will change the chordwise load distribution. Building the wing a bay longer will change the loads the lift struts see. The weight and balance of aircraft has an influence. As you can see the calculations need to be done for each particular aircraft. This is not an attempt to discourage you, as I intend to use round tube for my struts as streamline tube is difficult and expensive to get where I live, however the math for my aircraft may not suit yours.Regards Mike T. ----- Original Message -----
Hi John, there is no simple equation to tell you the various loads that a strut will see under all flight and landing conditions. However you can get close if you make several assumptions, such as the chord wise load distribution at maximum lift which will determine the difference in loads that the front and rear struts will see. Also the span wise load distribution at maximum lift which will determine the ratio of the load shared between the main struts and the cabane struts. If you have used longer cabane struts and some dihedral the angle of the main struts will be different as will the tension and compression loads they see. Using a different airfoil will change the chordwise load distribution. Building the wing a bay longer will change the loads the lift struts see. The weight and balance of aircraft has an influence. As you can see the calculations need to be done for each particular aircraft. This is not an attempt to discourage you, as I intend to use round tube for my struts as streamline tube is difficult and expensive to get where I live, however the math for my aircraft may not suit yours.Regards Mike T. ----- Original Message -----
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Mike Tunnicliffe
Not only each aircraft if they aren't built to the plans, but each of the several loading conditions - Stall at maneuvering speed,Gust at max cruise,Max gs at Vne, And these again for negative loads. Certainly the chordwise loads change for each of these. The spanwise loads might, too.No one said it was easy!David Paule ----- Original Message -----
Not only each aircraft if they aren't built to the plans, but each of the several loading conditions - Stall at maneuvering speed,Gust at max cruise,Max gs at Vne, And these again for negative loads. Certainly the chordwise loads change for each of these. The spanwise loads might, too.No one said it was easy!David Paule ----- Original Message -----
Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: "Skip Gadd"
John (PM Danger),Here I was, thinking that you wanted to know a simple method to determine whethera certain size of round 4130 tubing could be substituted for the 1934 specialstreamline tubing shown in the plans, and I was thinking about how there isNO SIMPLE ANSWER or formula to give, and then you tell us you're talking aboutwooden struts. There are so many variables (without even getting int the specificsof your unique plane)! There's the species of wood, the "quality" of theparticular pieces of wood used, the size and shape of the struts, the thicknessand number of laminations, the glue used, not to mention the "metal inserts".You mention that you are not an engineer. Well, as you know, I am an engineer,but I'm not an aeronautical engineer. Despite my background, I do not feel qualifiedto determine the suitability of wooden flying struts for my Piet, let alonesomeone else's. I think your best option would be to track down a builderthat has successfully built and flown (for a significant amount of time) a wooden-struttedPiet, and borrow that design (if they are willing to share it withyou). It sounds like you have built a set of struts based on "that looks about right".The flying struts are WAY too important to be approached in that manner. Likeyou say, a catastrophic failure in flight would really screw up your day. Bevery careful with this stuff.As much as I like the look of wooden struts I will be using steel struts on myplane.Bill C.Read this topic online here:http://forums.matronics.com/viewtopic.p ... __________
John (PM Danger),Here I was, thinking that you wanted to know a simple method to determine whethera certain size of round 4130 tubing could be substituted for the 1934 specialstreamline tubing shown in the plans, and I was thinking about how there isNO SIMPLE ANSWER or formula to give, and then you tell us you're talking aboutwooden struts. There are so many variables (without even getting int the specificsof your unique plane)! There's the species of wood, the "quality" of theparticular pieces of wood used, the size and shape of the struts, the thicknessand number of laminations, the glue used, not to mention the "metal inserts".You mention that you are not an engineer. Well, as you know, I am an engineer,but I'm not an aeronautical engineer. Despite my background, I do not feel qualifiedto determine the suitability of wooden flying struts for my Piet, let alonesomeone else's. I think your best option would be to track down a builderthat has successfully built and flown (for a significant amount of time) a wooden-struttedPiet, and borrow that design (if they are willing to share it withyou). It sounds like you have built a set of struts based on "that looks about right".The flying struts are WAY too important to be approached in that manner. Likeyou say, a catastrophic failure in flight would really screw up your day. Bevery careful with this stuff.As much as I like the look of wooden struts I will be using steel struts on myplane.Bill C.Read this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Robert Ray
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
RE: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: "Bill Church"
New this prop is about $1,900 according to the Prince website, it was custom made for a Pietenpol. I'd sell it for a lot less than $1,900. Does anyone need a prop for an A-75? It is in near new condition, and probably has less than 100hrs on it, although I don't know the exact number. If anyone is interested I'll take some good quality pictures, just send me an e-mail - steve(at)wotelectronics.com. It turns about 2,500 static on my A-75 I believe.Here is a picture from a few years ago, it is not on the plane now:http://www.wotelectronics.com/flying/GN ... .com/Steve RuseNorman, OK________________________________________________________________________________Subject: RE: Pietenpol-List: Re: lift struts for GN-1 /PietenpolDate: Tue, 20 Oct 2009 11:31:30 -0400
New this prop is about $1,900 according to the Prince website, it was custom made for a Pietenpol. I'd sell it for a lot less than $1,900. Does anyone need a prop for an A-75? It is in near new condition, and probably has less than 100hrs on it, although I don't know the exact number. If anyone is interested I'll take some good quality pictures, just send me an e-mail - steve(at)wotelectronics.com. It turns about 2,500 static on my A-75 I believe.Here is a picture from a few years ago, it is not on the plane now:http://www.wotelectronics.com/flying/GN ... .com/Steve RuseNorman, OK________________________________________________________________________________Subject: RE: Pietenpol-List: Re: lift struts for GN-1 /PietenpolDate: Tue, 20 Oct 2009 11:31:30 -0400
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Bill Church
this has probably already been said, or will be said a hundred times, but just in case someone new has not already heard it, the jury struts also prevent the struts from setting up a harmonic vibration that could result in a catastrophic strut or fitting failure. The jury struts MUST NOT be in the center of the strut in order to prevent the harmonic. If they are in the center, the strut would vibrate equally on each side of the jury strut, I.e. the same harmonic problem.Gene ----- Original Message -----
this has probably already been said, or will be said a hundred times, but just in case someone new has not already heard it, the jury struts also prevent the struts from setting up a harmonic vibration that could result in a catastrophic strut or fitting failure. The jury struts MUST NOT be in the center of the strut in order to prevent the harmonic. If they are in the center, the strut would vibrate equally on each side of the jury strut, I.e. the same harmonic problem.Gene ----- Original Message -----
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: _Bill Church_ (mailto:eng(at)canadianrogers.com)
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolI took that one to heart very seriously in the metal placement for the struts such that they are set for mounting above the half point rather than below. I do appreciate the reminder and added that tidbit to my build notes to insure that rule was not violated. Working with wood one needs to be really careful about throwing caution to the wind.I plan on metal for the jury struts stainless tubing I am thinking. All depends on price availability and fitting attachment points. Why invite corrosion if ya don't need too, I would prefer the added weight and strength of stainless rather than the reduction of weight of due to corrosion. Plus it looks really kool!JohnIn a message dated 10/21/2009 8:09:18 A.M. Eastern Daylight Time, generambo(at)msn.com writes:this has probably already been said, or will be said a hundred times, but just in case someone new has not already heard it, the jury struts also prevent the struts from setting up a harmonic vibration that could result in acatastrophic strut or fitting failure. The jury struts MUST NOT be in the center of the strut in order to prevent the harmonic. If they are in the center, the strut would vibrate equally on each side of the jury strut, I.e. the same harmonic problem. IGene----- Original Message -----
Subject: Re: Pietenpol-List: Re: lift struts for GN-1 /PietenpolI took that one to heart very seriously in the metal placement for the struts such that they are set for mounting above the half point rather than below. I do appreciate the reminder and added that tidbit to my build notes to insure that rule was not violated. Working with wood one needs to be really careful about throwing caution to the wind.I plan on metal for the jury struts stainless tubing I am thinking. All depends on price availability and fitting attachment points. Why invite corrosion if ya don't need too, I would prefer the added weight and strength of stainless rather than the reduction of weight of due to corrosion. Plus it looks really kool!JohnIn a message dated 10/21/2009 8:09:18 A.M. Eastern Daylight Time, generambo(at)msn.com writes:this has probably already been said, or will be said a hundred times, but just in case someone new has not already heard it, the jury struts also prevent the struts from setting up a harmonic vibration that could result in acatastrophic strut or fitting failure. The jury struts MUST NOT be in the center of the strut in order to prevent the harmonic. If they are in the center, the strut would vibrate equally on each side of the jury strut, I.e. the same harmonic problem. IGene----- Original Message -----
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: AMsafetyC(at)aol.com
FYI, most stainless tubing is 300 series annealed. That stuff has a strength considerably less than normalized 4130. And its yield strength is less than 6061-T6 aluminum.David Paule ----- Original Message -----
FYI, most stainless tubing is 300 series annealed. That stuff has a strength considerably less than normalized 4130. And its yield strength is less than 6061-T6 aluminum.David Paule ----- Original Message -----
Re: Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: santiago morete
Re: Pietenpol-List: lift struts for GN-1 /Pietenpol
Original Posted By: helspersew(at)aol.com
Pietenpol-List: lift struts for GN-1 /Pietenpol
Original Posted By: Ben Charvet
Re: Pietenpol-List: We have wings!
Original Posted By: helspersew(at)aol.com
Pietenpol-List: Re: We have wings!
Original Posted By: Jim Markle
WOW! That's cool.--------Mark - working on wingsRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Wed, 21 Oct 2009 15:39:20 -0400 (GMT-04:00)
WOW! That's cool.--------Mark - working on wingsRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Wed, 21 Oct 2009 15:39:20 -0400 (GMT-04:00)
Re: Pietenpol-List: We have wings!
Original Posted By: Ben Charvet
Subject: Re: Pietenpol-List: We have wings!She looks great congratulations!You got to love it when a plan comes togetherJohnIn a message dated 10/21/2009 1:33:44 P.M. Eastern Daylight Time, bcharvet(at)bellsouth.net writes:Probably one of the more exciting days in a 5 year Pietenpol build!Ben CharvetMims, FlStill hoping to fly in 09________________________________________________________________________________Date: Wed, 21 Oct 2009 18:01:01 -0400
Subject: Re: Pietenpol-List: We have wings!She looks great congratulations!You got to love it when a plan comes togetherJohnIn a message dated 10/21/2009 1:33:44 P.M. Eastern Daylight Time, bcharvet(at)bellsouth.net writes:Probably one of the more exciting days in a 5 year Pietenpol build!Ben CharvetMims, FlStill hoping to fly in 09________________________________________________________________________________Date: Wed, 21 Oct 2009 18:01:01 -0400
Re: Pietenpol-List: We have wings!
Original Posted By: shad bell
Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Michael Perez
[quote="moretesantiago(at)yahoo.c"]Hi Jon, I don't know if I can help you, since our Piet is not flying, but we have roundlift struts, 1"OD .049 wall, 1025 steel. That's stronger than necessary. Saludos Santiago Encontra las mejores recetas con Yahoo! Cocina. http://ar.mujer.yahoo.com/cocina/ > The round set of struts that came with my project are 1 1/8" O.D. x .035. I donot know what grade of steel they are and really do not know how to determinethat. I would like to think it is 4130 but will probably uses a lower gradefor my calculations.--------Jon CoxwellRecycle and preserve the planetRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Thu, 22 Oct 2009 17:10:44 -0700 (PDT)
[quote="moretesantiago(at)yahoo.c"]Hi Jon, I don't know if I can help you, since our Piet is not flying, but we have roundlift struts, 1"OD .049 wall, 1025 steel. That's stronger than necessary. Saludos Santiago Encontra las mejores recetas con Yahoo! Cocina. http://ar.mujer.yahoo.com/cocina/ > The round set of struts that came with my project are 1 1/8" O.D. x .035. I donot know what grade of steel they are and really do not know how to determinethat. I would like to think it is 4130 but will probably uses a lower gradefor my calculations.--------Jon CoxwellRecycle and preserve the planetRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Thu, 22 Oct 2009 17:10:44 -0700 (PDT)
Re: Pietenpol-List: Prop choices for Corvair
Original Posted By: Rick Holland
Subject: Re: Pietenpol-List: Prop choices for Corvair
Subject: Re: Pietenpol-List: Prop choices for Corvair
Re: Pietenpol-List: Prop choices for Corvair
Original Posted By: shad bell
Pietenpol-List: Re: lift struts for GN-1 /Pietenpol
Original Posted By: Dan Yocum
coxwelljon wrote:> ... If so it sounds like I am in the ball park.Jon,There is a thread on this list where it is already calculated:http://forums.matronics.com/viewtopic.p ... s,IvanRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 23 Oct 2009 10:58:40 -0500
coxwelljon wrote:> ... If so it sounds like I am in the ball park.Jon,There is a thread on this list where it is already calculated:http://forums.matronics.com/viewtopic.p ... s,IvanRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 23 Oct 2009 10:58:40 -0500
Re: exhaust manifold [was Re: Pietenpol-List: humped center section]
Original Posted By: Rick Holland
Subject: Re: exhaust manifold [was Re: Pietenpol-List: humped center section]
Subject: Re: exhaust manifold [was Re: Pietenpol-List: humped center section]
RE: exhaust manifold [was Re: Pietenpol-List: humped center section]
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Good to know Rick! Jim Boyer and I have bought some U-bend mandrels fromwww.magnumforce.com .... A little moreexpensive.Gary BootheCool, Ca.PietenpolWW Corvair Conversion, mountedTail done, Fuselage on gear(15 ribs down.) _____
Good to know Rick! Jim Boyer and I have bought some U-bend mandrels fromwww.magnumforce.com .... A little moreexpensive.Gary BootheCool, Ca.PietenpolWW Corvair Conversion, mountedTail done, Fuselage on gear(15 ribs down.) _____
exhaust manifold [was Re: Pietenpol-List: humped center section]
Original Posted By: Michael Perez
RE: Pietenpol-List: Push/pull tubes and rod ends
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Are you planning on re-designing the entire elevator control system withpushrods, requiring a pushrod attached to each elevator, a pushrod from thebellcrank to the rear stick and a pushrod between sticks? It probably willrequire an additional pushrod and bellcrank to enable you to pass underneaththe rear seat (where the cable from the stick to the bellcrank makes a bend,with the plans showing it just passing through a hole drilled in the wood -I added a pulley here). If so, figure out the yield strength of whatever alloy of aluminum youintend to use, then determine what area will be required to withstand theload (1760 lbs, if you want to equal the cable strength) without exceedingthat stress level. Use the formula Stress = Load divided by Area (s = P/A),and solve for area (A) since you know the load (P = 1760) and you know thestress (s = yield strength of your alloy times whatever safety factor youfeel like throwing in). Once you know the area, then determine what wallthickness and tube diameter will produce the required area. Of course,there will be machined fittings required on each end of the pushrods, androd end bearings to reduce the amount of slop.As an engineer, I have to wonder why are you doing this? The cables workwell. Any arrangement with pushrods is going to be much more complicated,due to the geometry of the airplane. Pushrods will end up being far moreexpensive and heavier. I don't understand what advantage you are trying toachieve here, other than to be "different". You could accomplish that bypainting it Pink.Jack PhillipsNX899JPRaleigh, NCEnjoying a rainy day by building the wings of my RV-10 in the basement _____
Are you planning on re-designing the entire elevator control system withpushrods, requiring a pushrod attached to each elevator, a pushrod from thebellcrank to the rear stick and a pushrod between sticks? It probably willrequire an additional pushrod and bellcrank to enable you to pass underneaththe rear seat (where the cable from the stick to the bellcrank makes a bend,with the plans showing it just passing through a hole drilled in the wood -I added a pulley here). If so, figure out the yield strength of whatever alloy of aluminum youintend to use, then determine what area will be required to withstand theload (1760 lbs, if you want to equal the cable strength) without exceedingthat stress level. Use the formula Stress = Load divided by Area (s = P/A),and solve for area (A) since you know the load (P = 1760) and you know thestress (s = yield strength of your alloy times whatever safety factor youfeel like throwing in). Once you know the area, then determine what wallthickness and tube diameter will produce the required area. Of course,there will be machined fittings required on each end of the pushrods, androd end bearings to reduce the amount of slop.As an engineer, I have to wonder why are you doing this? The cables workwell. Any arrangement with pushrods is going to be much more complicated,due to the geometry of the airplane. Pushrods will end up being far moreexpensive and heavier. I don't understand what advantage you are trying toachieve here, other than to be "different". You could accomplish that bypainting it Pink.Jack PhillipsNX899JPRaleigh, NCEnjoying a rainy day by building the wings of my RV-10 in the basement _____
Pietenpol-List: Push/pull tubes and rod ends
Original Posted By: Michael Perez
Re: Pietenpol-List: Push/pull tubes and rod ends
Original Posted By: Michael Perez
Re: Pietenpol-List: Push/pull tubes and rod ends
Original Posted By: helspersew(at)aol.com
Re: Pietenpol-List: Push/pull tubes and rod ends
Original Posted By: Michael Perez
The equation you introduced is effective for the pull-out strength of the threads in a hole. The "(shear load)" you mentioned is the shear stress that the material can take, not the applied load. A good (in fact, one of the best) sources for structural analysis is free:http://euler9.tripod.com/analysis/asm.htmlIt's not really for beginners, though, so be careful if this is new to you. This is reasonably comprehensive.While the Piet isn't an FAA certified airplane, it often makes sense to use the certification requirements for determining the loads. Federal Air Regulations, Part 23, covers this:http://www.flightsimaviation.com/data/F ... tmlControl system loads are covered in 23.395 and more to the point in 23.397:http://www.flightsimaviation.com/data/F ... 397.htmlAs you see, the control system doesn't need to be stronger than these forces applied to the control stick. It's a simple matter to go from there to the loads in any single part of the system.Without looking at the system you are designing, but thinking only of push-pull tubes, it strikes me that the major things to look at are:a) the end fittings, which can get complicated. Look at the holes, the pins, the clevis (if any) and the connection to the tube, including any welds or fasteners, and their holes if there are any.b) the tension strength of the tube, that is, accounting for any holes or threads,c) the compression strength,d) the Euler buckling strength,e) and finally the local crippling, sometimes referred to as D/t crippling. f) It's also important to make sure that the new system is no more flexible than the old one. You'll need to know the effective modulus of elasticity of the cabling, and that often seems to be around 11 x10^6 psi, based upon the nominal area. You can get better data from MIL-HDBK-5, I think. There might not be much, though, I simply don't remember. But the 11 msi value is ball-park.I'm sorry that I don't have a handy link to MIL-HDBK-5H, the best source for metal data, but after you download a copy, which should be free, look at the end of Chapter 2 for steel or 3 for aluminum; chapter 2.8 or 3.11. There are handy graphs of element properties for tubes, which include both forms of buckling. Incidentally, H is the best version. The newer letters miss some of the data more applicable to general aviation and are harder to use.David Paule ----- Original Message -----
The equation you introduced is effective for the pull-out strength of the threads in a hole. The "(shear load)" you mentioned is the shear stress that the material can take, not the applied load. A good (in fact, one of the best) sources for structural analysis is free:http://euler9.tripod.com/analysis/asm.htmlIt's not really for beginners, though, so be careful if this is new to you. This is reasonably comprehensive.While the Piet isn't an FAA certified airplane, it often makes sense to use the certification requirements for determining the loads. Federal Air Regulations, Part 23, covers this:http://www.flightsimaviation.com/data/F ... tmlControl system loads are covered in 23.395 and more to the point in 23.397:http://www.flightsimaviation.com/data/F ... 397.htmlAs you see, the control system doesn't need to be stronger than these forces applied to the control stick. It's a simple matter to go from there to the loads in any single part of the system.Without looking at the system you are designing, but thinking only of push-pull tubes, it strikes me that the major things to look at are:a) the end fittings, which can get complicated. Look at the holes, the pins, the clevis (if any) and the connection to the tube, including any welds or fasteners, and their holes if there are any.b) the tension strength of the tube, that is, accounting for any holes or threads,c) the compression strength,d) the Euler buckling strength,e) and finally the local crippling, sometimes referred to as D/t crippling. f) It's also important to make sure that the new system is no more flexible than the old one. You'll need to know the effective modulus of elasticity of the cabling, and that often seems to be around 11 x10^6 psi, based upon the nominal area. You can get better data from MIL-HDBK-5, I think. There might not be much, though, I simply don't remember. But the 11 msi value is ball-park.I'm sorry that I don't have a handy link to MIL-HDBK-5H, the best source for metal data, but after you download a copy, which should be free, look at the end of Chapter 2 for steel or 3 for aluminum; chapter 2.8 or 3.11. There are handy graphs of element properties for tubes, which include both forms of buckling. Incidentally, H is the best version. The newer letters miss some of the data more applicable to general aviation and are harder to use.David Paule ----- Original Message -----
Re: Pietenpol-List: Push/pull tubes and rod ends
Original Posted By: Ryan Mueller
Subject: Re: Pietenpol-List: Push/pull tubes and rod ends
Subject: Re: Pietenpol-List: Push/pull tubes and rod ends
Pietenpol-List: Re: Push/pull tubes and rod ends
Original Posted By: "Pieti Lowell"
Whoa - what comments are you responding to Mike?The only reply to your post that I saw was from Jack, and all I saw in his replywere sound reasons explaining why the cables are a better system FOR THIS AIRPLANE.As he stated, the geometry of the Air Camper will result in a heavierand more expensive linkage as compared to the cables. Tony Bingelis says thatpush/pull tubes MAY weigh less than a cable system. That will depend on the layoutof the airplane, and in this case, the control system has to go under theseat, and then get back up into alignment with the elevators and rudder. Cablescan change direction with the addition of a simple pulley, where push/pulltubes will require bellcranks - which one do you think is heavier? It is not possibleto run a tube straight from the firewall to the rudder in this airplane,unless you have a properly sized and located hole in your torso for the tubeto pass through. Also, in THIS airplane, the elevators are separate entities,so you would either have to redesign them so that they are tied together, orrun two push/pull tubes for the elevators.To quote your original post "I'm all about saving weight on my plane". Jack's replyexplained that the push/pull system will end up being heavier than the cablesystem. So what IS the motivation to change to the push/pull system?Regarding your request for a formula, the thing to keep in mind is that in designinga mechanism like a push/pull system, you need to analyze each componentand each connection in the system, and the loads that could be imposed on eachcomponent. Those loads are used to determine the size and shape that each componentwill assume. There are the different tubes that need material, diameterand wall thickness to be determined, and the size of all the threaded connections,and the design and positioning and fastening of the bellcranks, etc. It'snot simple. Not something that I would feel like spending a couple of days workingon - especially since there doesn't appear to be any benefit to changingthe system. Or do you know of a REAL benefit? (not just an opinion or guess)Bill C.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Push/pull tubes and rod ends
Whoa - what comments are you responding to Mike?The only reply to your post that I saw was from Jack, and all I saw in his replywere sound reasons explaining why the cables are a better system FOR THIS AIRPLANE.As he stated, the geometry of the Air Camper will result in a heavierand more expensive linkage as compared to the cables. Tony Bingelis says thatpush/pull tubes MAY weigh less than a cable system. That will depend on the layoutof the airplane, and in this case, the control system has to go under theseat, and then get back up into alignment with the elevators and rudder. Cablescan change direction with the addition of a simple pulley, where push/pulltubes will require bellcranks - which one do you think is heavier? It is not possibleto run a tube straight from the firewall to the rudder in this airplane,unless you have a properly sized and located hole in your torso for the tubeto pass through. Also, in THIS airplane, the elevators are separate entities,so you would either have to redesign them so that they are tied together, orrun two push/pull tubes for the elevators.To quote your original post "I'm all about saving weight on my plane". Jack's replyexplained that the push/pull system will end up being heavier than the cablesystem. So what IS the motivation to change to the push/pull system?Regarding your request for a formula, the thing to keep in mind is that in designinga mechanism like a push/pull system, you need to analyze each componentand each connection in the system, and the loads that could be imposed on eachcomponent. Those loads are used to determine the size and shape that each componentwill assume. There are the different tubes that need material, diameterand wall thickness to be determined, and the size of all the threaded connections,and the design and positioning and fastening of the bellcranks, etc. It'snot simple. Not something that I would feel like spending a couple of days workingon - especially since there doesn't appear to be any benefit to changingthe system. Or do you know of a REAL benefit? (not just an opinion or guess)Bill C.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Push/pull tubes and rod ends
Original Posted By: "David Paule"
Hosey Challis built his 8Th Piet, Challis Chafinch with a push-pull tube that operatedfrom the stick up to the wing centersection it eliminated the cross controlwires.This is the Piet that I flew for many years, all worked perfect, is in a Museumnow in EnglandPieti LowellRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Hosey Challis built his 8Th Piet, Challis Chafinch with a push-pull tube that operatedfrom the stick up to the wing centersection it eliminated the cross controlwires.This is the Piet that I flew for many years, all worked perfect, is in a Museumnow in EnglandPieti LowellRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Re: Pietenpol-List: Re: Push/pull tubes and rod ends
Original Posted By: "Bill Church"
Historically, the major benefit to a push rod control system compared to a cable control system is that the push rod system has lower friction since there's no need for the cable tension in the cable system. No preload tension, and you've eliminated a major part of the friction. Also, typically, they have rod-end or other bearings for the joints, again with lower friction.Another benefit is that they can be stiffer, but that's generally only beneficial for larger, faster aircraft.Push-rod systems are almost always heavier.There's an often unanticipated benefit of building per the plans: it reduces the chances of inadvertently designing in some unanticipated failure mode.So if weight or simplicity or safety matters, follow the plans.David Paule----- Original Message -----
Historically, the major benefit to a push rod control system compared to a cable control system is that the push rod system has lower friction since there's no need for the cable tension in the cable system. No preload tension, and you've eliminated a major part of the friction. Also, typically, they have rod-end or other bearings for the joints, again with lower friction.Another benefit is that they can be stiffer, but that's generally only beneficial for larger, faster aircraft.Push-rod systems are almost always heavier.There's an often unanticipated benefit of building per the plans: it reduces the chances of inadvertently designing in some unanticipated failure mode.So if weight or simplicity or safety matters, follow the plans.David Paule----- Original Message -----