Original Posted By: owner-pietenpol-list-server(at)matronics.com
--> Pietenpol-List message posted by: "Jack Phillips" Remember, that 3200 lbs I calculated had NO safety factor in it. That means, if you hit a 4 G bump in turbulance and you're flying at gross weight, you can expect complete failure instantly. Nobody designs a critical component with no safety factor. There are places to cut costs, and there are places to be very conservative. This is not a place to take risks. Even though you fly in Ohio and fields for forced landings are plentiful, they do no good if you are plunging to earth in your fuselage, looking up at your wing fluttering down lazily above you, due to cheap fittings letting go. Jack Phillips NX899JP "Icarus Plummet" Raleigh, NC -----Original Message-----
Pietenpol-List: Wing Strut Fork End
Pietenpol-List: Wing Strut Fork End
Original Posted By: norm
Re: Pietenpol-List: Wing Strut Fork End
Original Posted By: Michael Perez
Hi Michael,I used 7075 inserts and the J-3 forks. Two 1/4" bolts in each end of the strut. That's all you need. I would not use turnbuckle forks. They look too flimsy to me. Save up and by the good ones.Dan HelsperPoplar Grove, IL. -----Original Message-----
Hi Michael,I used 7075 inserts and the J-3 forks. Two 1/4" bolts in each end of the strut. That's all you need. I would not use turnbuckle forks. They look too flimsy to me. Save up and by the good ones.Dan HelsperPoplar Grove, IL. -----Original Message-----
Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: shad bell
Michael,Regarding the use of a turnbuckle fork end as a substitute for a wing strut fork,the short answer is ... NO.Never mind the hole size and throat opening on the fork - take a look at the diameterof the threaded portion. The -46 fork end has a 5/16" diameter threadedportion, whereas the Piper forks are 7/16" diameter. Assuming that both are madeof the same grade of steel, the 7/16" diameter will be capable of carryingtwice the load that the 5/16" diameter can.This isn't an item to scrimp on. Play it safe and use the real thing.Bill C.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Mon, 10 Jan 2011 16:55:33 -0800 (PST)
Michael,Regarding the use of a turnbuckle fork end as a substitute for a wing strut fork,the short answer is ... NO.Never mind the hole size and throat opening on the fork - take a look at the diameterof the threaded portion. The -46 fork end has a 5/16" diameter threadedportion, whereas the Piper forks are 7/16" diameter. Assuming that both are madeof the same grade of steel, the 7/16" diameter will be capable of carryingtwice the load that the 5/16" diameter can.This isn't an item to scrimp on. Play it safe and use the real thing.Bill C.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Mon, 10 Jan 2011 16:55:33 -0800 (PST)
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: gliderx5(at)comcast.net
RE: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By:> speedbrake(at)sbcglobal.net
When in doubt error on the safe side. Your life hangs on those small fittings. Yes they are expensive=2C we just bought a set last month for our cub struts for our piet. Is you life worth a few hundred dollars? Vic in Tulare.> Date: Mon=2C 10 Jan 2011 17:29:07 -0800
When in doubt error on the safe side. Your life hangs on those small fittings. Yes they are expensive=2C we just bought a set last month for our cub struts for our piet. Is you life worth a few hundred dollars? Vic in Tulare.> Date: Mon=2C 10 Jan 2011 17:29:07 -0800
RE: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Remember, that 3200 lbs I calculated had NO safety factor in it. Thatmeans, if you hit a 4 G bump in turbulance and you're flying at grossweight, you can expect complete failure instantly. Nobody designs a critical component with no safety factor. There are placesto cut costs, and there are places to be very conservative. This is not aplace to take risks. Even though you fly in Ohio and fields for forcedlandings are plentiful, they do no good if you are plunging to earth in yourfuselage, looking up at your wing fluttering down lazily above you, due tocheap fittings letting go.Jack PhillipsNX899JP "Icarus Plummet"Raleigh, NC-----Original Message-----
Remember, that 3200 lbs I calculated had NO safety factor in it. Thatmeans, if you hit a 4 G bump in turbulance and you're flying at grossweight, you can expect complete failure instantly. Nobody designs a critical component with no safety factor. There are placesto cut costs, and there are places to be very conservative. This is not aplace to take risks. Even though you fly in Ohio and fields for forcedlandings are plentiful, they do no good if you are plunging to earth in yourfuselage, looking up at your wing fluttering down lazily above you, due tocheap fittings letting go.Jack PhillipsNX899JP "Icarus Plummet"Raleigh, NC-----Original Message-----
Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: "Bill Church"
The cub forks I have, cheap from ebay by the way, donot have any narrow shaft between the threaded portionand the head. We all are concentrating on tension butwhat about compression? With even a slight misalignmentthat narrow shaft is more prone to bend under G loads.And we are not working to 10 to the fifth decimal pointshere are we so there are misalignments. And not necessarilyin the strut assembly itself.Clif"Perfection is achieved, not when there is nothing more toadd, but when there is nothing left to take away."Antoine de Saint-Exupery> I understand what everyone is saying...stop screwing around and use what > is known to work. But No one has explained why the fittings I propose are > not a good substitute. > Again, sorry for the rant.>> Michael Perez________________________________________________________________________________Subject: Pietenpol-List: Re: Wing Strut Fork End
The cub forks I have, cheap from ebay by the way, donot have any narrow shaft between the threaded portionand the head. We all are concentrating on tension butwhat about compression? With even a slight misalignmentthat narrow shaft is more prone to bend under G loads.And we are not working to 10 to the fifth decimal pointshere are we so there are misalignments. And not necessarilyin the strut assembly itself.Clif"Perfection is achieved, not when there is nothing more toadd, but when there is nothing left to take away."Antoine de Saint-Exupery> I understand what everyone is saying...stop screwing around and use what > is known to work. But No one has explained why the fittings I propose are > not a good substitute. > Again, sorry for the rant.>> Michael Perez________________________________________________________________________________Subject: Pietenpol-List: Re: Wing Strut Fork End
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: EDWARD BARCHIK
=0A=0A=0A=0A=0AThere are 3 factors that decide selection of the Fork-end of the main strut:=0A=0A=0A-=0A=0A=0A1) tension load, easily understood and both J-3 fork end and a Turnbuckle style fork can handle the required load.=0A=0A=0A-=0A=0A=0A2) compression load, often over looked but flying-in turbulence often experienced, J-3 fork can handle this, Turnbuckle style can not.=0A=0A=0ARemember that turnbuckles are designed-for cable use, no compression loads there.=0A=0A=0A-=0A=0A=0A3) overlooked even more often is thread strength, diameter & length.=0A=0A=0AFor a steel fork end to work as designed the diameter should be same a as the-height of the nut insert-(nut part to be of the same material)=0A=0A=0A=0AIn other words a 5/16 Fork tread needs to have 5/16 nut height, if you tap in to the strut your tread dept needs to be at least 5/16.=0A=0A=0ANote: nut/ strut threads-of the same steel material,- more length is always better, rolled threads are better than cut/ tapped threads.=0A=0A=0A-=0A=0A=0AI use the J-3 style fork end with steel struts and the weld-in treaded purpose build nut insert.=0A=0A=0A-=0A=0A=0ANow if you choose to use aluminum struts and tap your own treads be aware that aluminum has a lower tensile strength than steel.=0A=0A=0ASo compensate by tapping a deep/ long thread in to the best aluminum you can get.=0A=0A=0AYour fork tread might not be long enough.=0A=0A=0AYou might need to consider a steel insert.=0A=0A=0A-=0A=0A=0ATurnbuckles assemblies-with brass center piece use the same principle, the tread depth is much longer ( 6-8 X ) than the diameter of the tread.=0A=0A=0A-=0A=0A=0AI did not sleep in a Holiday-inn express last night, but am a mechanical engineer by profession=0A=0A=0A-=0A=0A=0AHans=0A=0A=0A-=0A=0A=0ANX15KV=0A=0A=0A-=0A=0A=0A=0A________________________________________________________________________________
=0A=0A=0A=0A=0AThere are 3 factors that decide selection of the Fork-end of the main strut:=0A=0A=0A-=0A=0A=0A1) tension load, easily understood and both J-3 fork end and a Turnbuckle style fork can handle the required load.=0A=0A=0A-=0A=0A=0A2) compression load, often over looked but flying-in turbulence often experienced, J-3 fork can handle this, Turnbuckle style can not.=0A=0A=0ARemember that turnbuckles are designed-for cable use, no compression loads there.=0A=0A=0A-=0A=0A=0A3) overlooked even more often is thread strength, diameter & length.=0A=0A=0AFor a steel fork end to work as designed the diameter should be same a as the-height of the nut insert-(nut part to be of the same material)=0A=0A=0A=0AIn other words a 5/16 Fork tread needs to have 5/16 nut height, if you tap in to the strut your tread dept needs to be at least 5/16.=0A=0A=0ANote: nut/ strut threads-of the same steel material,- more length is always better, rolled threads are better than cut/ tapped threads.=0A=0A=0A-=0A=0A=0AI use the J-3 style fork end with steel struts and the weld-in treaded purpose build nut insert.=0A=0A=0A-=0A=0A=0ANow if you choose to use aluminum struts and tap your own treads be aware that aluminum has a lower tensile strength than steel.=0A=0A=0ASo compensate by tapping a deep/ long thread in to the best aluminum you can get.=0A=0A=0AYour fork tread might not be long enough.=0A=0A=0AYou might need to consider a steel insert.=0A=0A=0A-=0A=0A=0ATurnbuckles assemblies-with brass center piece use the same principle, the tread depth is much longer ( 6-8 X ) than the diameter of the tread.=0A=0A=0A-=0A=0A=0AI did not sleep in a Holiday-inn express last night, but am a mechanical engineer by profession=0A=0A=0A-=0A=0A=0AHans=0A=0A=0A-=0A=0A=0ANX15KV=0A=0A=0A-=0A=0A=0A=0A________________________________________________________________________________
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: Kip and Beth Gardner
=0A=0A =0A=0AWhen you find that out I would like to know all the details and pics, I =0Aalready have my wooden struts and have been trying to come up with an attachment =0Amethod or design that's going to be safe and work well. So please share your =0Aresults.=0A-=0AThanks=0A-=0AJohn-=0A-=0A=0AIn a message dated 1/11/2011 9:59:49 A.M. Eastern Standard Time, =0Akipandbeth(at)earthlink.net writes:=0AWhile =0A we're on this topic, does anyone know of a way to make wooden lift struts =0A adjustable? I'm going to make mine from some # of -laminations, with at =0A least one layer of carbon fiber strands within the full strut, and probably =0A cross-wise layerings for extra reinforcement at the ends (still figuring out =0A the details, but similar to what Jim Markle did on his cabana struts). =0A -From the images I've found on various people's sites so far, it looks =0A like the only option for adjustment would be to remake the terminal fittings, =0A and I imagine there's a practical length limit with regard to twisting loads =0A (?) on those. -If adjustment is difficult or impossible (short of making =0A new struts), I'd think I'd want to put this off until just about everything =0A else is completed and I'm working on the initial rigging of the completed =0A wings? =0A =0A Any comments? -Thanks!=0A =0A Kip Gardner=0A =0A =0A =0A =0A On Jan 11, 2011, at 9:14 AM, Ryan Mueller wrote:=0A Give Wag-Aero a call, they manufacture them: =0A =0A http://www.wagaero.com/contact.html=0A On Tue, Jan 11, 2011 at 8:01 AM, Michael Perez =0A wrote:=0A =0A =0A =0A =0A =0A =0A =0A =0A =0A I =0A see the points of a few on this list and laugh at some of the =0A others, but I appreciate those who take the time to explain =0A their points of view and take the time to listen to mine. I =0A may ask around here at work and what people think. If I find =0A any good intell. along the way, I'll post it.By the =0A way, anyone know what the Piper forks are rated at? What =0A material? I could not find anything on them.- =0A Michael PerezKaretaker =0A Aerowww.karetakeraero.com=0A =0A =0A " target="_blank">http://www.matronics.com/Navigator?Piet ... tributiont href="http://www.matronics.com/Navigator?Piet ... __________
=0A=0A =0A=0AWhen you find that out I would like to know all the details and pics, I =0Aalready have my wooden struts and have been trying to come up with an attachment =0Amethod or design that's going to be safe and work well. So please share your =0Aresults.=0A-=0AThanks=0A-=0AJohn-=0A-=0A=0AIn a message dated 1/11/2011 9:59:49 A.M. Eastern Standard Time, =0Akipandbeth(at)earthlink.net writes:=0AWhile =0A we're on this topic, does anyone know of a way to make wooden lift struts =0A adjustable? I'm going to make mine from some # of -laminations, with at =0A least one layer of carbon fiber strands within the full strut, and probably =0A cross-wise layerings for extra reinforcement at the ends (still figuring out =0A the details, but similar to what Jim Markle did on his cabana struts). =0A -From the images I've found on various people's sites so far, it looks =0A like the only option for adjustment would be to remake the terminal fittings, =0A and I imagine there's a practical length limit with regard to twisting loads =0A (?) on those. -If adjustment is difficult or impossible (short of making =0A new struts), I'd think I'd want to put this off until just about everything =0A else is completed and I'm working on the initial rigging of the completed =0A wings? =0A =0A Any comments? -Thanks!=0A =0A Kip Gardner=0A =0A =0A =0A =0A On Jan 11, 2011, at 9:14 AM, Ryan Mueller wrote:=0A Give Wag-Aero a call, they manufacture them: =0A =0A http://www.wagaero.com/contact.html=0A On Tue, Jan 11, 2011 at 8:01 AM, Michael Perez =0A wrote:=0A =0A =0A =0A =0A =0A =0A =0A =0A =0A I =0A see the points of a few on this list and laugh at some of the =0A others, but I appreciate those who take the time to explain =0A their points of view and take the time to listen to mine. I =0A may ask around here at work and what people think. If I find =0A any good intell. along the way, I'll post it.By the =0A way, anyone know what the Piper forks are rated at? What =0A material? I could not find anything on them.- =0A Michael PerezKaretaker =0A Aerowww.karetakeraero.com=0A =0A =0A " target="_blank">http://www.matronics.com/Navigator?Piet ... tributiont href="http://www.matronics.com/Navigator?Piet ... __________
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: Michael Perez
Michael,If you are hell-bent on trying them, then do so. Nobody is going to stop you, and you can prove us all wrong.....................until the end.Dan HelsperPoplar Grove, IL. -----Original Message-----
Michael,If you are hell-bent on trying them, then do so. Nobody is going to stop you, and you can prove us all wrong.....................until the end.Dan HelsperPoplar Grove, IL. -----Original Message-----
RE: Pietenpol-List: Re: Tail wheel
Original Posted By: owner-pietenpol-list-server(at)matronics.com [owner-pietenpol-list-serve
Rick, This is a woodshop class. The students are 3rd and 4th year students, Juniors and Seniors. We hope to complete project in spring 2012. Ed________________________________
Rick, This is a woodshop class. The students are 3rd and 4th year students, Juniors and Seniors. We hope to complete project in spring 2012. Ed________________________________
RE: Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Just to be sure what we are discussing, the AN 665-80RA (picture is a 21) isa no-no for wing struts.JackDSM _____
Just to be sure what we are discussing, the AN 665-80RA (picture is a 21) isa no-no for wing struts.JackDSM _____
Pietenpol-List: Re: Tail wheel
Original Posted By: Michael Perez
The setup I used was a Matco tailwheel AS&S PN# 06-01615 and single leaf springPN# 06-14500. Untested but I think will work fine and relatively inexpensive.--------Adrian MWinnipeg, MBCanadaRead this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/dscn ... ______Date: Tue, 11 Jan 2011 05:20:22 -0800 (PST)
The setup I used was a Matco tailwheel AS&S PN# 06-01615 and single leaf springPN# 06-14500. Untested but I think will work fine and relatively inexpensive.--------Adrian MWinnipeg, MBCanadaRead this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/dscn ... ______Date: Tue, 11 Jan 2011 05:20:22 -0800 (PST)
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: Michael Perez
RE: Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: Michael Perez
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: Ryan Mueller
Subject: Re: Pietenpol-List: Re: Wing Strut Fork End
Subject: Re: Pietenpol-List: Re: Wing Strut Fork End
Re: Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: Ryan Mueller
Subject: Re: Re: Pietenpol-List: Re: Wing Strut Fork End
Subject: Re: Re: Pietenpol-List: Re: Wing Strut Fork End
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: hvandervoo(at)aol.com
While we're on this topic, does anyone know of a way to make wooden lift struts adjustable? I'm going to make mine from some # of laminations, with at least one layer of carbon fiber strands within the full strut, and probably cross-wise layerings for extra reinforcement at the ends (still figuring out the details, but similar to what Jim Markle did on his cabana struts). =46rom the images I've found on various people's sites so far, it looks like the only option for adjustment would be to remake the terminal fittings, and I imagine there's a practical length limit with regard to twisting loads (?) on those. If adjustment is difficult or impossible (short of making new struts), I'd think I'd want to put this off until just about everything else is completed and I'm working on the initial rigging of the completed wings?Any comments? Thanks!Kip GardnerOn Jan 11, 2011, at 9:14 AM, Ryan Mueller wrote:> Give Wag-Aero a call, they manufacture them:> > http://www.wagaero.com/contact.html> > On Tue, Jan 11, 2011 at 8:01 AM, Michael Perez wrote:> I see the points of a few on this list and laugh at some of the others, but I appreciate those who take the time to explain their points of view and take the time to listen to mine. I may ask around here at work and what people think. If I find any good intell. along the way, I'll post it.> > By the way, anyone know what the Piper forks are rated at? What material? I could not find anything on them. > > Michael Perez> Karetaker Aero> www.karetakeraero.com> > > > > " target="_blank">http://www.matronics.com/Navigator?Pietenpol-List> tp://forums.matronics.com> _blank">http://www.matronics.com/contribution> > > > > ________________________________________________________________________________Subject: Re: Pietenpol-List: Re: Wing Strut Fork End
While we're on this topic, does anyone know of a way to make wooden lift struts adjustable? I'm going to make mine from some # of laminations, with at least one layer of carbon fiber strands within the full strut, and probably cross-wise layerings for extra reinforcement at the ends (still figuring out the details, but similar to what Jim Markle did on his cabana struts). =46rom the images I've found on various people's sites so far, it looks like the only option for adjustment would be to remake the terminal fittings, and I imagine there's a practical length limit with regard to twisting loads (?) on those. If adjustment is difficult or impossible (short of making new struts), I'd think I'd want to put this off until just about everything else is completed and I'm working on the initial rigging of the completed wings?Any comments? Thanks!Kip GardnerOn Jan 11, 2011, at 9:14 AM, Ryan Mueller wrote:> Give Wag-Aero a call, they manufacture them:> > http://www.wagaero.com/contact.html> > On Tue, Jan 11, 2011 at 8:01 AM, Michael Perez wrote:> I see the points of a few on this list and laugh at some of the others, but I appreciate those who take the time to explain their points of view and take the time to listen to mine. I may ask around here at work and what people think. If I find any good intell. along the way, I'll post it.> > By the way, anyone know what the Piper forks are rated at? What material? I could not find anything on them. > > Michael Perez> Karetaker Aero> www.karetakeraero.com> > > > > " target="_blank">http://www.matronics.com/Navigator?Pietenpol-List> tp://forums.matronics.com> _blank">http://www.matronics.com/contribution> > > > > ________________________________________________________________________________Subject: Re: Pietenpol-List: Re: Wing Strut Fork End
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: "Douwe Blumberg"
Subject: Re: Pietenpol-List: Re: Wing Strut Fork EndWhen you find that out I would like to know all the details and pics, I already have my wooden struts and have been trying to come up with an attachment method or design that's going to be safe and work well. So please shareyour results.ThanksJohn In a message dated 1/11/2011 9:59:49 A.M. Eastern Standard Time, kipandbeth(at)earthlink.net writes:While we're on this topic, does anyone know of a way to make wooden lift struts adjustable? I'm going to make mine from some # of laminations, with at least one layer of carbon fiber strands within the full strut, and probably cross-wise layerings for extra reinforcement at the ends (still figuring out the details, but similar to what Jim Markle did on his cabana struts). From the images I've found on various people's sites so far, it lookslike the only option for adjustment would be to remake the terminal fittings, and I imagine there's a practical length limit with regard to twisting loads (?) on those. If adjustment is difficult or impossible (short of makingnew struts), I'd think I'd want to put this off until just about everything else is completed and I'm working on the initial rigging of the completed wings? Any comments? Thanks!Kip GardnerOn Jan 11, 2011, at 9:14 AM, Ryan Mueller wrote:Give Wag-Aero a call, they manufacture them: _http://www.wagaero.com/contact.html_ (http://www.wagaero.com/contact.html) On Tue, Jan 11, 2011 at 8:01 AM, Michael Perez wrote: I see the points of a few on this list and laugh at some of the others, but I appreciate those who take the time to explain their points of viewand take the time to listen to mine. I may ask around here at work and what people think. If I find any good intell. along the way, I'll post it.By the way, anyone know what the Piper forks are rated at? What material? I could not find anything on them. Michael PerezKaretaker Aero_www.karetakeraero.com_ (http://www.karetakeraero.com/) " target="_blank">http://www.matronics.com/Navigator?Pietenpol-List _tp://forums.matronics.com_ (tp://forums.matronics.com/) _blank">http://www.matronics.com/contributionhr ... ronics.com href="http://www.matronics.com/contribution"> ... ntribution (http://www.matronics.com/Navigator?Pietenpol-List) (http://www.matronics.com/contribution) ________________________________________________________________________________
Subject: Re: Pietenpol-List: Re: Wing Strut Fork EndWhen you find that out I would like to know all the details and pics, I already have my wooden struts and have been trying to come up with an attachment method or design that's going to be safe and work well. So please shareyour results.ThanksJohn In a message dated 1/11/2011 9:59:49 A.M. Eastern Standard Time, kipandbeth(at)earthlink.net writes:While we're on this topic, does anyone know of a way to make wooden lift struts adjustable? I'm going to make mine from some # of laminations, with at least one layer of carbon fiber strands within the full strut, and probably cross-wise layerings for extra reinforcement at the ends (still figuring out the details, but similar to what Jim Markle did on his cabana struts). From the images I've found on various people's sites so far, it lookslike the only option for adjustment would be to remake the terminal fittings, and I imagine there's a practical length limit with regard to twisting loads (?) on those. If adjustment is difficult or impossible (short of makingnew struts), I'd think I'd want to put this off until just about everything else is completed and I'm working on the initial rigging of the completed wings? Any comments? Thanks!Kip GardnerOn Jan 11, 2011, at 9:14 AM, Ryan Mueller wrote:Give Wag-Aero a call, they manufacture them: _http://www.wagaero.com/contact.html_ (http://www.wagaero.com/contact.html) On Tue, Jan 11, 2011 at 8:01 AM, Michael Perez wrote: I see the points of a few on this list and laugh at some of the others, but I appreciate those who take the time to explain their points of viewand take the time to listen to mine. I may ask around here at work and what people think. If I find any good intell. along the way, I'll post it.By the way, anyone know what the Piper forks are rated at? What material? I could not find anything on them. Michael PerezKaretaker Aero_www.karetakeraero.com_ (http://www.karetakeraero.com/) " target="_blank">http://www.matronics.com/Navigator?Pietenpol-List _tp://forums.matronics.com_ (tp://forums.matronics.com/) _blank">http://www.matronics.com/contributionhr ... ronics.com href="http://www.matronics.com/contribution"> ... ntribution (http://www.matronics.com/Navigator?Pietenpol-List) (http://www.matronics.com/contribution) ________________________________________________________________________________
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: rmueller23(at)gmail.com
I Have to agree w/everyone here. There has to ba a reason those lift forks are a lot more expensive that turnbarrel forks. My guess is they are a lot stronger in more ways than one.Doug DeverIn beautiful Stow OhioDate: Tue=2C 11 Jan 2011 08:05:58 -0600Subject: Re: Pietenpol-List: Re: Wing Strut Fork End
I Have to agree w/everyone here. There has to ba a reason those lift forks are a lot more expensive that turnbarrel forks. My guess is they are a lot stronger in more ways than one.Doug DeverIn beautiful Stow OhioDate: Tue=2C 11 Jan 2011 08:05:58 -0600Subject: Re: Pietenpol-List: Re: Wing Strut Fork End
RE: Pietenpol-List: Re: Tail wheel
Original Posted By: owner-pietenpol-list-server(at)matronics.com [owner-pietenpol-list-server(at)matronics.com]
Thanks Adrian, kids love the project.________________________________________
Thanks Adrian, kids love the project.________________________________________
Pietenpol-List: Re: Tail wheel
Original Posted By: Lawrence Williams
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By:> AMsafetyC(at)aol.com
That would probably do it. It would have to be designed so the threaded end of the fork would not need a 'relief' hole drilled into the end of the strut to accommodate adjustments, or you create a pocket for rot to develop in, no matter how well you seal it. Also, the end grain of the strut would need to be exposed for inspection purposes, for the same reason.On Jan 11, 2011, at 12:04 PM, Michael Perez wrote:> If I may, could it be as simple as welding a threaded boss onto or > between a couple steel plates. These plates then bolt to the strut > and the strut fork threads into the boss? Some type of transition > piece to get you from wood to steel for the fork.>> Michael Perez> Karetaker Aero> www.karetakeraero.com>> --- On Tue, 1/11/11, AMsafetyC(at)aol.com wrote:>
That would probably do it. It would have to be designed so the threaded end of the fork would not need a 'relief' hole drilled into the end of the strut to accommodate adjustments, or you create a pocket for rot to develop in, no matter how well you seal it. Also, the end grain of the strut would need to be exposed for inspection purposes, for the same reason.On Jan 11, 2011, at 12:04 PM, Michael Perez wrote:> If I may, could it be as simple as welding a threaded boss onto or > between a couple steel plates. These plates then bolt to the strut > and the strut fork threads into the boss? Some type of transition > piece to get you from wood to steel for the fork.>> Michael Perez> Karetaker Aero> www.karetakeraero.com>> --- On Tue, 1/11/11, AMsafetyC(at)aol.com wrote:>
RE: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: speedbrake(at)sbcglobal.net
You could always cadmium plate them that is what is done to bolts and seaplane fittings.Doug DeverIn beautiful Stow OhioDate: Tue=2C 11 Jan 2011 07:53:49 -0800
You could always cadmium plate them that is what is done to bolts and seaplane fittings.Doug DeverIn beautiful Stow OhioDate: Tue=2C 11 Jan 2011 07:53:49 -0800
Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: "Bill Church"
Larry - Burning it would be environmentally disastrous. I have a much better solution.Just send me your address and I will come and take it off your handsand you will never have to worry about it again! :)Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Wing Strut Fork End
Larry - Burning it would be environmentally disastrous. I have a much better solution.Just send me your address and I will come and take it off your handsand you will never have to worry about it again! :)Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: Ben Charvet
Michael wrote:"Ah, yeah, I read all posts related to my original question. This safety factorof 3, is that a standard factor or a number you came up with Bill?"and"I see the points of a few on this list and laugh at some of the others, but ..."I guess I must be one of the ones whose points you laugh at.Whatever... In response to your question, the FS of 3 is based on general engineering practice.I am a mechanical engineer, but not an aeronautical engineer, and have never claimedto be one, so I did a little research today, and have discovered that itis standard practice in aircraft design to use a Factor of safety of 1.5. Thisseems a little counter-intuitive, since the Factor of Safety used for aircraftdesign is half of that used in general practice, and only about one sevenththat used for elevator cables (the things used to move people up and down inbuildings, not the things at the back of the airplane). However, it has becomea standard practice, because weight saving is critical for an aircraft to work.In order to be able to design inside this restrictive envelope, the aircrafthas to operate within certain well-defined parameters (max speed, load, maneuvers,etc.). Additionally, the materials and practices used for aircraft manufactureare subject to stringent qualifications and standards (e.g. AN hardware,AC 43.13-1B, etc.). And finally, the actual aircraft are inspected more carefullyand regularly than ordinary equipment.So, the short answer is that for aircraft design, the accepted minimum Factor ofSafety is 1.5. And the limit load for normal aircraft use is +4g, which canbe reached by recovering from a dive. Maybe not an activity that is planned, butconceivable that it could occur during normal flight. So the design load isthen 6g. The Piper wing strut fittings may actually be slightly stronger thanthat required for this specific purpose, since the Piper struts have only oneconnection point at the bottom (Vee struts), but, as Jack explained, the frontstruts carry the larger portion of the load anyway. Since these fittings arereadily available, and designed for this very purpose (wing strut fitting foran aircraft of similar size and function), why not use them? From the AircraftSpruce website, the largest turnbuckle fork they list 161-80RS, which is ratedfor 8000 lb, the price is about $40. The Piper fork is about $85. $45 differencex 4 pcs = less than $200 "savings". Is it really worth it?It's been said that an engineer is someone that calculates to five decimal places,and then multiplies the final answer by 2. I guess that's me.I'd hate to see someone suffer for the sake of saving a few dollars.I'll shut up now.Bill C.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 11 Jan 2011 19:20:56 -0500
Michael wrote:"Ah, yeah, I read all posts related to my original question. This safety factorof 3, is that a standard factor or a number you came up with Bill?"and"I see the points of a few on this list and laugh at some of the others, but ..."I guess I must be one of the ones whose points you laugh at.Whatever... In response to your question, the FS of 3 is based on general engineering practice.I am a mechanical engineer, but not an aeronautical engineer, and have never claimedto be one, so I did a little research today, and have discovered that itis standard practice in aircraft design to use a Factor of safety of 1.5. Thisseems a little counter-intuitive, since the Factor of Safety used for aircraftdesign is half of that used in general practice, and only about one sevenththat used for elevator cables (the things used to move people up and down inbuildings, not the things at the back of the airplane). However, it has becomea standard practice, because weight saving is critical for an aircraft to work.In order to be able to design inside this restrictive envelope, the aircrafthas to operate within certain well-defined parameters (max speed, load, maneuvers,etc.). Additionally, the materials and practices used for aircraft manufactureare subject to stringent qualifications and standards (e.g. AN hardware,AC 43.13-1B, etc.). And finally, the actual aircraft are inspected more carefullyand regularly than ordinary equipment.So, the short answer is that for aircraft design, the accepted minimum Factor ofSafety is 1.5. And the limit load for normal aircraft use is +4g, which canbe reached by recovering from a dive. Maybe not an activity that is planned, butconceivable that it could occur during normal flight. So the design load isthen 6g. The Piper wing strut fittings may actually be slightly stronger thanthat required for this specific purpose, since the Piper struts have only oneconnection point at the bottom (Vee struts), but, as Jack explained, the frontstruts carry the larger portion of the load anyway. Since these fittings arereadily available, and designed for this very purpose (wing strut fitting foran aircraft of similar size and function), why not use them? From the AircraftSpruce website, the largest turnbuckle fork they list 161-80RS, which is ratedfor 8000 lb, the price is about $40. The Piper fork is about $85. $45 differencex 4 pcs = less than $200 "savings". Is it really worth it?It's been said that an engineer is someone that calculates to five decimal places,and then multiplies the final answer by 2. I guess that's me.I'd hate to see someone suffer for the sake of saving a few dollars.I'll shut up now.Bill C.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Tue, 11 Jan 2011 19:20:56 -0500
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: Michael Perez
If I may, I'll add my $.02. My disclaimer: I do have an aerospace engineering degree,but that was > 35 years ago, and I have not worked as an aero engineer(I got into computer software early on.) In dealing with aircraft structures you need to take into account both limit andultimate loads, since our safety factor is a relatively slim 1.5. So the 4gwe've been referencing here is the limit load to design to. At any load up tothe point, everything in the structure must be able to withstand it without anypermanent deformation (i.e. nothing can bend and take a permanent set.) Thestructure will bend and flex, but once you're back on the ground everything willspring back to the way it was. Now take all those loads you've calculated, multiply 'em by 1.5. Now every bitof the structure has to withstand those loads without failing, but they may takea permanent bend. Where this is important on our Piet's is that the differencein load between the yield point of wood and its breaking point is less thana factor of 1.5. So if your structure (such as wood struts) just meets the designlimit loads, it's likely to break before reaching the ultimate loads. Formost metals that we'll use, the difference between yield and breaking is greaterthan 1.5, so so can design to the 4g. I don't imagine many of us would intentionallystress a Pietenpol to 4g's, but as Bill said, various maneuvers couldput you up there.Again, as Bill and Jack have mentioned, the front spar will carry more load thanthe rear, particularly at high angles of attack. And, if you ever hit those4g's it will be at a high angle of attack. If you want to really get into themath, there was a good series of articles on stress analysis of a strut bracedrectangular wing (Baby Ace) in Sport Aviation, Nov. & Dec. 1963, and Sept. 1965.(No, I'm not that old, but I do have a reprint of the articles in an old EAApublication, "Design, vol. 3".Another factor to consider is the category of the airplane. From what I remember(don't have any of my old texts on hand) normal category aircraft are designedto a limit load of 3.8g. Utility aircraft (Cessna 150/152 are I believe inthe utility category, as is the Bonanza and others) are designed to 4g, and aerobaticaircraft to 6g. (Although most aerobatic aircraft are now designed andflown to loads well above 6g. The RedBull racers have pulled over 12g momentarily!)KenOn Jan 11, 2011, at 4:04 PM, Bill Church wrote:> > Michael wrote:> "Ah, yeah, I read all posts related to my original question. This safety factorof 3, is that a standard factor or a number you came up with Bill?"> and> "I see the points of a few on this list and laugh at some of the others, but..."> > I guess I must be one of the ones whose points you laugh at.> Whatever... > > In response to your question, the FS of 3 is based on general engineering practice.> I am a mechanical engineer, but not an aeronautical engineer, and have neverclaimed to be one, so I did a little research today, and have discovered thatit is standard practice in aircraft design to use a Factor of safety of 1.5. Thisseems a little counter-intuitive, since the Factor of Safety used for aircraftdesign is half of that used in general practice, and only about one sevenththat used for elevator cables (the things used to move people up and down inbuildings, not the things at the back of the airplane). However, it has becomea standard practice, because weight saving is critical for an aircraft to work.In order to be able to design inside this restrictive envelope, the aircrafthas to operate within certain well-defined parameters (max speed, load, maneuvers,etc.). Additionally, the materials and practices used for aircraft manufactureare subject to stringent qualifications and standards (e.g. AN hardware,AC 43.13-1B, etc.). And finally, the actual airc!> raft are inspected more carefully and regularly than ordinary equipment.> So, the short answer is that for aircraft design, the accepted minimum Factorof Safety is 1.5. And the limit load for normal aircraft use is +4g, which canbe reached by recovering from a dive. Maybe not an activity that is planned,but conceivable that it could occur during normal flight. So the design loadis then 6g. The Piper wing strut fittings may actually be slightly stronger thanthat required for this specific purpose, since the Piper struts have only oneconnection point at the bottom (Vee struts), but, as Jack explained, the frontstruts carry the larger portion of the load anyway. Since these fittings arereadily available, and designed for this very purpose (wing strut fitting foran aircraft of similar size and function), why not use them? From the AircraftSpruce website, the largest turnbuckle fork they list 161-80RS, which is ratedfor 8000 lb, the price is about $40. The Piper fork is about $85. $45 differencex 4 pcs = less than $200 "savings". Is it real!> ly worth it?> It's been said that an engineer is someone that calculates to five decimal places,and then multiplies the final answer by 2. I guess that's me.> I'd hate to see someone suffer for the sake of saving a few dollars.> I'll shut up now.> > Bill C.> > > > > Read this topic online here:> > http://forums.matronics.com/viewtopic.p ... 594#326594> > > > > > > > > > ________________________________________________________________________________Date: Tue, 11 Jan 2011 18:05:11 -0800 (PST)
If I may, I'll add my $.02. My disclaimer: I do have an aerospace engineering degree,but that was > 35 years ago, and I have not worked as an aero engineer(I got into computer software early on.) In dealing with aircraft structures you need to take into account both limit andultimate loads, since our safety factor is a relatively slim 1.5. So the 4gwe've been referencing here is the limit load to design to. At any load up tothe point, everything in the structure must be able to withstand it without anypermanent deformation (i.e. nothing can bend and take a permanent set.) Thestructure will bend and flex, but once you're back on the ground everything willspring back to the way it was. Now take all those loads you've calculated, multiply 'em by 1.5. Now every bitof the structure has to withstand those loads without failing, but they may takea permanent bend. Where this is important on our Piet's is that the differencein load between the yield point of wood and its breaking point is less thana factor of 1.5. So if your structure (such as wood struts) just meets the designlimit loads, it's likely to break before reaching the ultimate loads. Formost metals that we'll use, the difference between yield and breaking is greaterthan 1.5, so so can design to the 4g. I don't imagine many of us would intentionallystress a Pietenpol to 4g's, but as Bill said, various maneuvers couldput you up there.Again, as Bill and Jack have mentioned, the front spar will carry more load thanthe rear, particularly at high angles of attack. And, if you ever hit those4g's it will be at a high angle of attack. If you want to really get into themath, there was a good series of articles on stress analysis of a strut bracedrectangular wing (Baby Ace) in Sport Aviation, Nov. & Dec. 1963, and Sept. 1965.(No, I'm not that old, but I do have a reprint of the articles in an old EAApublication, "Design, vol. 3".Another factor to consider is the category of the airplane. From what I remember(don't have any of my old texts on hand) normal category aircraft are designedto a limit load of 3.8g. Utility aircraft (Cessna 150/152 are I believe inthe utility category, as is the Bonanza and others) are designed to 4g, and aerobaticaircraft to 6g. (Although most aerobatic aircraft are now designed andflown to loads well above 6g. The RedBull racers have pulled over 12g momentarily!)KenOn Jan 11, 2011, at 4:04 PM, Bill Church wrote:> > Michael wrote:> "Ah, yeah, I read all posts related to my original question. This safety factorof 3, is that a standard factor or a number you came up with Bill?"> and> "I see the points of a few on this list and laugh at some of the others, but..."> > I guess I must be one of the ones whose points you laugh at.> Whatever... > > In response to your question, the FS of 3 is based on general engineering practice.> I am a mechanical engineer, but not an aeronautical engineer, and have neverclaimed to be one, so I did a little research today, and have discovered thatit is standard practice in aircraft design to use a Factor of safety of 1.5. Thisseems a little counter-intuitive, since the Factor of Safety used for aircraftdesign is half of that used in general practice, and only about one sevenththat used for elevator cables (the things used to move people up and down inbuildings, not the things at the back of the airplane). However, it has becomea standard practice, because weight saving is critical for an aircraft to work.In order to be able to design inside this restrictive envelope, the aircrafthas to operate within certain well-defined parameters (max speed, load, maneuvers,etc.). Additionally, the materials and practices used for aircraft manufactureare subject to stringent qualifications and standards (e.g. AN hardware,AC 43.13-1B, etc.). And finally, the actual airc!> raft are inspected more carefully and regularly than ordinary equipment.> So, the short answer is that for aircraft design, the accepted minimum Factorof Safety is 1.5. And the limit load for normal aircraft use is +4g, which canbe reached by recovering from a dive. Maybe not an activity that is planned,but conceivable that it could occur during normal flight. So the design loadis then 6g. The Piper wing strut fittings may actually be slightly stronger thanthat required for this specific purpose, since the Piper struts have only oneconnection point at the bottom (Vee struts), but, as Jack explained, the frontstruts carry the larger portion of the load anyway. Since these fittings arereadily available, and designed for this very purpose (wing strut fitting foran aircraft of similar size and function), why not use them? From the AircraftSpruce website, the largest turnbuckle fork they list 161-80RS, which is ratedfor 8000 lb, the price is about $40. The Piper fork is about $85. $45 differencex 4 pcs = less than $200 "savings". Is it real!> ly worth it?> It's been said that an engineer is someone that calculates to five decimal places,and then multiplies the final answer by 2. I guess that's me.> I'd hate to see someone suffer for the sake of saving a few dollars.> I'll shut up now.> > Bill C.> > > > > Read this topic online here:> > http://forums.matronics.com/viewtopic.p ... 594#326594> > > > > > > > > > ________________________________________________________________________________Date: Tue, 11 Jan 2011 18:05:11 -0800 (PST)
Pietenpol-List: Re: Tail wheel
Original Posted By: "Greg Cardinal"
Flyboy wrote:> I'm a new guy, woodshop teacher, building a Piet with 12 students. Our fuselageis making progress. What tailwheel is recommended for the Piet. We plan onusing 600-6 tires and springs instead of bungee cords. Would appreciate anyhelp possible. Flyboy from Berwick PAHey Teach, can you hit enter every once in awhile?
--------BlueRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Flyboy wrote:> I'm a new guy, woodshop teacher, building a Piet with 12 students. Our fuselageis making progress. What tailwheel is recommended for the Piet. We plan onusing 600-6 tires and springs instead of bungee cords. Would appreciate anyhelp possible. Flyboy from Berwick PAHey Teach, can you hit enter every once in awhile?
--------BlueRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: "Kenneth Howe"
The article Ken mentions is located on Chris Tracy's website here:http://www.westcoastpiet.com/construction.htmGreg C.----- Original Message -----
The article Ken mentions is located on Chris Tracy's website here:http://www.westcoastpiet.com/construction.htmGreg C.----- Original Message -----
Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: "amsafetyc(at)aol.com"
ken(at)cooper-mtn.com wrote:> Another factor to consider is the category of the airplane. From what I remember(don't have any of my old texts on hand) normal category aircraft are designedto a limit load of 3.8g. Utility aircraft (Cessna 150/152 are I believe inthe utility category, as is the Bonanza and others) are designed to 4g, andaerobatic aircraft to 6g. (Although most aerobatic aircraft are now designed andflown to loads well above 6g. The RedBull racers have pulled over 12g momentarily!)> > Ken> > On Jan 11, 2011, at 4:04 PM, Bill Church wrote:> > > > > > > > Correction: The 150/152 are in the "Oh my GOD that's ugly" catagory. Theydon't have to worry about air loads, they don't fly by aerodynamic laws. They'reso ugly they repel the earth. > > Michael wrote:> > "Ah, yeah, I read all posts related to my original question. This safety factorof 3, is that a standard factor or a number you came up with Bill?"> > and> > "I see the points of a few on this list and laugh at some of the others, but..."> > > > I guess I must be one of the ones whose points you laugh at.> > Whatever... > > > > In response to your question, the FS of 3 is based on general engineeringpractice.> > I am a mechanical engineer, but not an aeronautical engineer, and have neverclaimed to be one, so I did a little research today, and have discovered thatit is standard practice in aircraft design to use a Factor of safety of 1.5.This seems a little counter-intuitive, since the Factor of Safety used for aircraftdesign is half of that used in general practice, and only about one sevenththat used for elevator cables (the things used to move people up and downin buildings, not the things at the back of the airplane). However, it has becomea standard practice, because weight saving is critical for an aircraft towork. In order to be able to design inside this restrictive envelope, the aircrafthas to operate within certain well-defined parameters (max speed, load,maneuvers, etc.). Additionally, the materials and practices used for aircraftmanufacture are subject to stringent qualifications and standards (e.g. AN hardware,AC 43.13-1B, etc.). And finally, the actual airc!> > raft are inspected more carefully and regularly than ordinary equipment.> > So, the short answer is that for aircraft design, the accepted minimum Factorof Safety is 1.5. And the limit load for normal aircraft use is +4g, whichcan be reached by recovering from a dive. Maybe not an activity that is planned,but conceivable that it could occur during normal flight. So the design loadis then 6g. The Piper wing strut fittings may actually be slightly strongerthan that required for this specific purpose, since the Piper struts have onlyone connection point at the bottom (Vee struts), but, as Jack explained, thefront struts carry the larger portion of the load anyway. Since these fittingsare readily available, and designed for this very purpose (wing strut fittingfor an aircraft of similar size and function), why not use them? From the AircraftSpruce website, the largest turnbuckle fork they list 161-80RS, which israted for 8000 lb, the price is about $40. The Piper fork is about $85. $45difference x 4 pcs = less than $200 "savings". Is it real!> > ly worth it?> > It's been said that an engineer is someone that calculates to five decimalplaces, and then multiplies the final answer by 2. I guess that's me.> > I'd hate to see someone suffer for the sake of saving a few dollars.> > I'll shut up now.> > > > Bill C.> > > > > > > > > > Read this topic online here:> > > > http://forums.matronics.com/viewtopic.p ... 594#326594> > > > > > > > > > > > > > > > > > > > > > > > >
--------Brad "DOMIT" SmithFirst rule of ground school: This is the ground... don't hit it going fast.Read this topic online here:http://forums.matronics.com/viewtopic.p ... __________
ken(at)cooper-mtn.com wrote:> Another factor to consider is the category of the airplane. From what I remember(don't have any of my old texts on hand) normal category aircraft are designedto a limit load of 3.8g. Utility aircraft (Cessna 150/152 are I believe inthe utility category, as is the Bonanza and others) are designed to 4g, andaerobatic aircraft to 6g. (Although most aerobatic aircraft are now designed andflown to loads well above 6g. The RedBull racers have pulled over 12g momentarily!)> > Ken> > On Jan 11, 2011, at 4:04 PM, Bill Church wrote:> > > > > > > > Correction: The 150/152 are in the "Oh my GOD that's ugly" catagory. Theydon't have to worry about air loads, they don't fly by aerodynamic laws. They'reso ugly they repel the earth. > > Michael wrote:> > "Ah, yeah, I read all posts related to my original question. This safety factorof 3, is that a standard factor or a number you came up with Bill?"> > and> > "I see the points of a few on this list and laugh at some of the others, but..."> > > > I guess I must be one of the ones whose points you laugh at.> > Whatever... > > > > In response to your question, the FS of 3 is based on general engineeringpractice.> > I am a mechanical engineer, but not an aeronautical engineer, and have neverclaimed to be one, so I did a little research today, and have discovered thatit is standard practice in aircraft design to use a Factor of safety of 1.5.This seems a little counter-intuitive, since the Factor of Safety used for aircraftdesign is half of that used in general practice, and only about one sevenththat used for elevator cables (the things used to move people up and downin buildings, not the things at the back of the airplane). However, it has becomea standard practice, because weight saving is critical for an aircraft towork. In order to be able to design inside this restrictive envelope, the aircrafthas to operate within certain well-defined parameters (max speed, load,maneuvers, etc.). Additionally, the materials and practices used for aircraftmanufacture are subject to stringent qualifications and standards (e.g. AN hardware,AC 43.13-1B, etc.). And finally, the actual airc!> > raft are inspected more carefully and regularly than ordinary equipment.> > So, the short answer is that for aircraft design, the accepted minimum Factorof Safety is 1.5. And the limit load for normal aircraft use is +4g, whichcan be reached by recovering from a dive. Maybe not an activity that is planned,but conceivable that it could occur during normal flight. So the design loadis then 6g. The Piper wing strut fittings may actually be slightly strongerthan that required for this specific purpose, since the Piper struts have onlyone connection point at the bottom (Vee struts), but, as Jack explained, thefront struts carry the larger portion of the load anyway. Since these fittingsare readily available, and designed for this very purpose (wing strut fittingfor an aircraft of similar size and function), why not use them? From the AircraftSpruce website, the largest turnbuckle fork they list 161-80RS, which israted for 8000 lb, the price is about $40. The Piper fork is about $85. $45difference x 4 pcs = less than $200 "savings". Is it real!> > ly worth it?> > It's been said that an engineer is someone that calculates to five decimalplaces, and then multiplies the final answer by 2. I guess that's me.> > I'd hate to see someone suffer for the sake of saving a few dollars.> > I'll shut up now.> > > > Bill C.> > > > > > > > > > Read this topic online here:> > > > http://forums.matronics.com/viewtopic.p ... 594#326594> > > > > > > > > > > > > > > > > > > > > > > > >
--------Brad "DOMIT" SmithFirst rule of ground school: This is the ground... don't hit it going fast.Read this topic online here:http://forums.matronics.com/viewtopic.p ... __________Re: Pietenpol-List: Adjustable Wood Wing Strut Fitting
Original Posted By: Owen Davies
Subject: Re: Pietenpol-List: Adjustable Wood Wing Strut FittingWhich is the reason for embedded metal at each end and midway not halfway points able to hold thru bolting with less chance of tearing out. Taking advantage of experienced builder comments on setting up a vibration at jury strut location half way rather than a sorta midway offset position. Its that safety thing in me that says a little metalic insurance is not a bad thing even with a nominal weight penalty its peace of mind assurance. JohnSent via DROID on Verizon Wireless-----Original message-----
Subject: Re: Pietenpol-List: Adjustable Wood Wing Strut FittingWhich is the reason for embedded metal at each end and midway not halfway points able to hold thru bolting with less chance of tearing out. Taking advantage of experienced builder comments on setting up a vibration at jury strut location half way rather than a sorta midway offset position. Its that safety thing in me that says a little metalic insurance is not a bad thing even with a nominal weight penalty its peace of mind assurance. JohnSent via DROID on Verizon Wireless-----Original message-----
Re: Pietenpol-List: Adjustable Wood Wing Strut Fitting
Original Posted By: Owen Davies
> RE: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By:> owner-pietenpol-list-server(at)matronics.com
> --> Pietenpol-List message posted> by: "Jack Phillips" > > Remember, that 3200 lbs I calculated had NO safety factor> in it. That> means, if you hit a 4 G bump in turbulance and you're> flying at gross> weight, you can expect complete failure instantly. > > Nobody designs a critical component with no safety> factor. There are places> to cut costs, and there are places to be very> conservative. This is not a> place to take risks. Even though you fly in Ohio and> fields for forced> landings are plentiful, they do no good if you are plunging> to earth in your> fuselage, looking up at your wing fluttering down lazily> above you, due to> cheap fittings letting go.> > Jack Phillips> NX899JP "Icarus Plummet"> Raleigh, NC> > -----Original Message-----
> --> Pietenpol-List message posted> by: "Jack Phillips" > > Remember, that 3200 lbs I calculated had NO safety factor> in it. That> means, if you hit a 4 G bump in turbulance and you're> flying at gross> weight, you can expect complete failure instantly. > > Nobody designs a critical component with no safety> factor. There are places> to cut costs, and there are places to be very> conservative. This is not a> place to take risks. Even though you fly in Ohio and> fields for forced> landings are plentiful, they do no good if you are plunging> to earth in your> fuselage, looking up at your wing fluttering down lazily> above you, due to> cheap fittings letting go.> > Jack Phillips> NX899JP "Icarus Plummet"> Raleigh, NC> > -----Original Message-----
> RE: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By:> owner-pietenpol-list-server(at)matronics.com
> --> Pietenpol-List message posted> by: "Jack Phillips" > > Remember, that 3200 lbs I calculated had NO safety factor> in it. That> means, if you hit a 4 G bump in turbulance and you're> flying at gross> weight, you can expect complete failure instantly. > > Nobody designs a critical component with no safety> factor. There are places> to cut costs, and there are places to be very> conservative. This is not a> place to take risks. Even though you fly in Ohio and> fields for forced> landings are plentiful, they do no good if you are plunging> to earth in your> fuselage, looking up at your wing fluttering down lazily> above you, due to> cheap fittings letting go.> > Jack Phillips> NX899JP "Icarus Plummet"> Raleigh, NC> > -----Original Message-----
> --> Pietenpol-List message posted> by: "Jack Phillips" > > Remember, that 3200 lbs I calculated had NO safety factor> in it. That> means, if you hit a 4 G bump in turbulance and you're> flying at gross> weight, you can expect complete failure instantly. > > Nobody designs a critical component with no safety> factor. There are places> to cut costs, and there are places to be very> conservative. This is not a> place to take risks. Even though you fly in Ohio and> fields for forced> landings are plentiful, they do no good if you are plunging> to earth in your> fuselage, looking up at your wing fluttering down lazily> above you, due to> cheap fittings letting go.> > Jack Phillips> NX899JP "Icarus Plummet"> Raleigh, NC> > -----Original Message-----
> Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: "Ray Krause"
>> When you find that out I would like to know all the details and > pics, I already have my wooden struts and have been trying to come > up with an attachment method or design that's going to be safe and > work well. So please share your results.>> Thanks>> John>> In a message dated 1/11/2011 9:59:49 A.M. Eastern Standard Time, kipandbeth(at)earthlink.net> writes:> While we're on this topic, does anyone know of a way to make wooden > lift struts adjustable? I'm going to make mine from some # of > laminations, with at least one layer of carbon fiber strands within > the full strut, and probably cross-wise layerings for extra > reinforcement at the ends (still figuring out the details, but > similar to what Jim Markle did on his cabana struts). >From the > images I've found on various people's sites so far, it looks like > the only option for adjustment would be to remake the terminal > fittings, and I imagine there's a practical length limit with regard > to twisting loads (?) on those. If adjustment is difficult or > impossible (short of making new struts), I'd think I'd want to put > this off until just about everything else is completed and I'm > working on the initial rigging of the completed wings?>> Any comments? Thanks!>> Kip Gardner>>> On Jan 11, 2011, at 9:14 AM, Ryan Mueller wrote:>>> Give Wag-Aero a call, they manufacture them:>>>> http://www.wagaero.com/contact.html>>>> On Tue, Jan 11, 2011 at 8:01 AM, Michael Perez > > wrote:>> I see the points of a few on this list and laugh at some of the >> others, but I appreciate those who take the time to explain their >> points of view and take the time to listen to mine. I may ask >> around here at work and what people think. If I find any good >> intell. along the way, I'll post it.>>>> By the way, anyone know what the Piper forks are rated at? What >> material? I could not find anything on them.>>>> Michael Perez>> Karetaker Aero>> www.karetakeraero.com>>>>>>>>>> " target="_blank">http://www.matronics.com/Navigator?Pietenpol-List>> tp://forums.matronics.com>> _blank">http://www.matronics.com/contribution>>>>>>>>>> href="http://www.matronics.com/Navigator?Piet ... enpol-List>> href="http://forums.matronics.com/">http://fo ... ronics.com>> href="http://www.matronics.com/contribution"> ... ntribution>>>>> ===================================> t> href="http://www.matronics.com/Navigator?Piet ... enpol-List> ==========> ms.matronics.com/">http://forums.matronics.com> ==========> tp://www.matronics.com/contribution">http:// ... ntribution> ===================================>> http://www.matronics.com/Navigw" target="_blank" href="http://forums.matronics.com > ">http://forums.mat> =========>>________________________________________________________________________________
>> When you find that out I would like to know all the details and > pics, I already have my wooden struts and have been trying to come > up with an attachment method or design that's going to be safe and > work well. So please share your results.>> Thanks>> John>> In a message dated 1/11/2011 9:59:49 A.M. Eastern Standard Time, kipandbeth(at)earthlink.net> writes:> While we're on this topic, does anyone know of a way to make wooden > lift struts adjustable? I'm going to make mine from some # of > laminations, with at least one layer of carbon fiber strands within > the full strut, and probably cross-wise layerings for extra > reinforcement at the ends (still figuring out the details, but > similar to what Jim Markle did on his cabana struts). >From the > images I've found on various people's sites so far, it looks like > the only option for adjustment would be to remake the terminal > fittings, and I imagine there's a practical length limit with regard > to twisting loads (?) on those. If adjustment is difficult or > impossible (short of making new struts), I'd think I'd want to put > this off until just about everything else is completed and I'm > working on the initial rigging of the completed wings?>> Any comments? Thanks!>> Kip Gardner>>> On Jan 11, 2011, at 9:14 AM, Ryan Mueller wrote:>>> Give Wag-Aero a call, they manufacture them:>>>> http://www.wagaero.com/contact.html>>>> On Tue, Jan 11, 2011 at 8:01 AM, Michael Perez > > wrote:>> I see the points of a few on this list and laugh at some of the >> others, but I appreciate those who take the time to explain their >> points of view and take the time to listen to mine. I may ask >> around here at work and what people think. If I find any good >> intell. along the way, I'll post it.>>>> By the way, anyone know what the Piper forks are rated at? What >> material? I could not find anything on them.>>>> Michael Perez>> Karetaker Aero>> www.karetakeraero.com>>>>>>>>>> " target="_blank">http://www.matronics.com/Navigator?Pietenpol-List>> tp://forums.matronics.com>> _blank">http://www.matronics.com/contribution>>>>>>>>>> href="http://www.matronics.com/Navigator?Piet ... enpol-List>> href="http://forums.matronics.com/">http://fo ... ronics.com>> href="http://www.matronics.com/contribution"> ... ntribution>>>>> ===================================> t> href="http://www.matronics.com/Navigator?Piet ... enpol-List> ==========> ms.matronics.com/">http://forums.matronics.com> ==========> tp://www.matronics.com/contribution">http:// ... ntribution> ===================================>> http://www.matronics.com/Navigw" target="_blank" href="http://forums.matronics.com > ">http://forums.mat> =========>>________________________________________________________________________________
Re: Pietenpol-List: Re: Wing Strut Fork End
Original Posted By: Doug Dever
There are 3 factors that decide selection of the Fork-end of the main strut:1) tension load=2C easily understood and both J-3 fork end and a Turnbuckle style fork can handle the required load.2) compression load=2C often over looked but flying in turbulence often experienced=2C J-3 fork can handle this=2C Turnbuckle style can not.Remember that turnbuckles are designed for cable use=2C no compression loads there.3) overlooked even more often is thread strength=2C diameter & length.For a steel fork end to work as designed the diameter should be same a as the height of the nut insert (nut part to be of the same material)In other words a 5/16 Fork tread needs to have 5/16 nut height=2C if you tap in to the strut your tread dept needs to be at least 5/16.Note: nut/ strut threads of the same steel material=2C more length is always better=2C rolled threads are better than cut/ tapped threads.I use the J-3 style fork end with steel struts and the weld-in treaded purpose build nut insert.Now if you choose to use aluminum struts and tap your own treads be aware that aluminum has a lower tensile strength than steel.So compensate by tapping a deep/ long thread in to the best aluminum you can get.Your fork tread might not be long enough.You might need to consider a steel insert.Turnbuckles assemblies with brass center piece use the same principle=2C the tread depth is much longer ( 6-8 X ) than the diameter of the tread.I did not sleep in a Holiday-inn express last night=2C but am a mechanical engineer by professionHansNX15KV ________________________________________________________________________________
There are 3 factors that decide selection of the Fork-end of the main strut:1) tension load=2C easily understood and both J-3 fork end and a Turnbuckle style fork can handle the required load.2) compression load=2C often over looked but flying in turbulence often experienced=2C J-3 fork can handle this=2C Turnbuckle style can not.Remember that turnbuckles are designed for cable use=2C no compression loads there.3) overlooked even more often is thread strength=2C diameter & length.For a steel fork end to work as designed the diameter should be same a as the height of the nut insert (nut part to be of the same material)In other words a 5/16 Fork tread needs to have 5/16 nut height=2C if you tap in to the strut your tread dept needs to be at least 5/16.Note: nut/ strut threads of the same steel material=2C more length is always better=2C rolled threads are better than cut/ tapped threads.I use the J-3 style fork end with steel struts and the weld-in treaded purpose build nut insert.Now if you choose to use aluminum struts and tap your own treads be aware that aluminum has a lower tensile strength than steel.So compensate by tapping a deep/ long thread in to the best aluminum you can get.Your fork tread might not be long enough.You might need to consider a steel insert.Turnbuckles assemblies with brass center piece use the same principle=2C the tread depth is much longer ( 6-8 X ) than the diameter of the tread.I did not sleep in a Holiday-inn express last night=2C but am a mechanical engineer by professionHansNX15KV ________________________________________________________________________________