Original Posted By: "Gene Rambo"
Need some advise, I am contemplating making my wheel struts out of wood, andfor that purpose I have designed a bracket from three pieces of metal thatwill be welded together. I am a little uncertain of the angel between thebottom of the fuselage and the strut .. If anybody could help I sure wouldappreciate it.Dane________________________________________________________________________________
Pietenpol-List: Wheel Strut Brackets
Re: Pietenpol-List: Wheel Strut Brackets
Original Posted By: Lars Hulgreen
it has been done, but a little different configuration, by Frank Pavliga. You might want to look at ones built to his plans, there are a lot of them out there.Gene ----- Original Message -----
it has been done, but a little different configuration, by Frank Pavliga. You might want to look at ones built to his plans, there are a lot of them out there.Gene ----- Original Message -----
Re: Pietenpol-List: help, please!
Original Posted By: helspersew(at)aol.com
I am reaching the point where I am starting assembly and need some specific information that I have seen on here before but cannot find now:1. I have seen the dimensions to change the elevator bellcrank so that the cables (1 do not touch the leading edge of the stab) and (2 do not get tight/slack during movement through their range). The first requires raising the bellcrank, the second is a difference in the distance between the holes for the cables;2. what is the source for the tailskid spring that most closely matches the one in the plans;Can someone help me with these??Gene________________________________________________________________________________Subject: Re: Pietenpol-List: help, please!Date: Sat, 14 Jun 2008 19:35:43 -0400
I am reaching the point where I am starting assembly and need some specific information that I have seen on here before but cannot find now:1. I have seen the dimensions to change the elevator bellcrank so that the cables (1 do not touch the leading edge of the stab) and (2 do not get tight/slack during movement through their range). The first requires raising the bellcrank, the second is a difference in the distance between the holes for the cables;2. what is the source for the tailskid spring that most closely matches the one in the plans;Can someone help me with these??Gene________________________________________________________________________________Subject: Re: Pietenpol-List: help, please!Date: Sat, 14 Jun 2008 19:35:43 -0400
Pietenpol-List: help, please!
Original Posted By: "walt evans"
Gene;If you look at the Piet drawings that show the bellcrank and the elevator horn,you'll find that the distance from center to center of the actuator holes onthe bellcrank is 7-3/4" (3-7/8" each way from the pivot center). The distancefrom center to center of the holes on the horn is 7-1/4". Thus there is a differencebetween the bellcrank and the horn, and what that does is change theactuation ratio. For a certain displacement of the bellcrank (and stick), a somewhatlarger displacement of the elevator occurs. This is fine. What we haveis a classic "four-bar linkage" and it all works when things are square.The problem comes when we change the relationship between the pivot centers ofthe bellcrank and the horn but still try to maintain the axis centers vertical(keep the bellcrank straight up and down with the elevators neutral). With onlya slight displacement, it isn't bad but in the Piet it's enough to throw thegeometry off and create slack in the cables when the stick is displaced.To remove all the error, you mount the bellcrank pivot center in a direct linewith the elevator pivot center when both the bellcrank and the horn are exactlyvertical. I think this is what John Dilatush did on "Mountain Piet", and othershave done the same, but the problem then becomes that you absolutely, positivelymust have pulleys under the pilot's seat to displace the control cablesup to the bellcrank... a rubbing block or fairlead guide just won't cut it withthat much change in direction of the cables as they head up to the bellcrank.Get some popsicle sticks, thumbtacks, and string and make a model. You'll seewhat I mean.Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________Date: Sat, 14 Jun 2008 21:51:27 -0400
Gene;If you look at the Piet drawings that show the bellcrank and the elevator horn,you'll find that the distance from center to center of the actuator holes onthe bellcrank is 7-3/4" (3-7/8" each way from the pivot center). The distancefrom center to center of the holes on the horn is 7-1/4". Thus there is a differencebetween the bellcrank and the horn, and what that does is change theactuation ratio. For a certain displacement of the bellcrank (and stick), a somewhatlarger displacement of the elevator occurs. This is fine. What we haveis a classic "four-bar linkage" and it all works when things are square.The problem comes when we change the relationship between the pivot centers ofthe bellcrank and the horn but still try to maintain the axis centers vertical(keep the bellcrank straight up and down with the elevators neutral). With onlya slight displacement, it isn't bad but in the Piet it's enough to throw thegeometry off and create slack in the cables when the stick is displaced.To remove all the error, you mount the bellcrank pivot center in a direct linewith the elevator pivot center when both the bellcrank and the horn are exactlyvertical. I think this is what John Dilatush did on "Mountain Piet", and othershave done the same, but the problem then becomes that you absolutely, positivelymust have pulleys under the pilot's seat to displace the control cablesup to the bellcrank... a rubbing block or fairlead guide just won't cut it withthat much change in direction of the cables as they head up to the bellcrank.Get some popsicle sticks, thumbtacks, and string and make a model. You'll seewhat I mean.Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________Date: Sat, 14 Jun 2008 21:51:27 -0400
Re: Pietenpol-List: Wheel Strut Brackets
Original Posted By: Lars Hulgreen
DaneThe problem with your question is that the angle will change depending what configuration of wheels you use. If you are going to use 21" motorcycle wheels I will go out and measure tomorrow. If you are using a 6.00-6 it will be different and my numbers wont help.It looks to me just looking at your drawings, your brackets might be too narrow. Which drawings are you basing these on? The drawings in the Flying Glider manuals indicate 1 3/4" between mounting holes. That will interfere with the ash beam that is on the fuse floor.Also, The tangs that attach to the lift struts should carry thru being one solid piece. You wouldnt want a weld to break there.Beautiful CAD drawings.Dick N. ----- Original Message -----
DaneThe problem with your question is that the angle will change depending what configuration of wheels you use. If you are going to use 21" motorcycle wheels I will go out and measure tomorrow. If you are using a 6.00-6 it will be different and my numbers wont help.It looks to me just looking at your drawings, your brackets might be too narrow. Which drawings are you basing these on? The drawings in the Flying Glider manuals indicate 1 3/4" between mounting holes. That will interfere with the ash beam that is on the fuse floor.Also, The tangs that attach to the lift struts should carry thru being one solid piece. You wouldnt want a weld to break there.Beautiful CAD drawings.Dick N. ----- Original Message -----
Re: Pietenpol-List: Wheel Strut Brackets
Original Posted By: Lars Hulgreen
DaneThis drawing is close to the way I built my fittings.They are slightly modified brackets based on the wood landing gear plans. I change one thing from the drawing, the lift strut strap that touches the bottom of the fuselage went strait and was welded to a cross brace connected to the other side. The bottom strap was then used for the cross cable brace. These pictures might help explain it better. http://westcoastpiet.com/images/Chris%2 ... G_2448.JPG and http://westcoastpiet.com/images/Chris%2 ... G_2977.JPG . Although I was a bit intimidated by them, they were not hard to fabricate.As for the angles to make all the bends, I drew a front view of the fuselage to scale and placed the axel where I wanted it below the fuselage and simply drew in the wood legs. I then measured the angles on the drawing. I used CAD but it also worked fine on paper. Chris TracySacramento, CaWebsite at http://www.WestCoastPiet.com ----- Original Message -----
DaneThis drawing is close to the way I built my fittings.They are slightly modified brackets based on the wood landing gear plans. I change one thing from the drawing, the lift strut strap that touches the bottom of the fuselage went strait and was welded to a cross brace connected to the other side. The bottom strap was then used for the cross cable brace. These pictures might help explain it better. http://westcoastpiet.com/images/Chris%2 ... G_2448.JPG and http://westcoastpiet.com/images/Chris%2 ... G_2977.JPG . Although I was a bit intimidated by them, they were not hard to fabricate.As for the angles to make all the bends, I drew a front view of the fuselage to scale and placed the axel where I wanted it below the fuselage and simply drew in the wood legs. I then measured the angles on the drawing. I used CAD but it also worked fine on paper. Chris TracySacramento, CaWebsite at http://www.WestCoastPiet.com ----- Original Message -----
Re: Pietenpol-List: help, please!
Original Posted By: walt evans
thanks to all for telling me to "build to the plans", and I think my airplane is probably closest to the plans of any I have seen, but I know that someone, maybe Ken Perkins, came up with a correction to the geometry of the bellcrank that eliminates the slack cables and keeps them the same tension throughout. At one time, I had made notes as to how it worked, but I cannot find them now. I do not think it was as simple as making the distance between the holes the same as on the elevator horns and stick controls, but it might have been. I think it had something to do with the bellcrank hinge not being in line with the holes for the cables, so there is some other measurement that works that someone arrived at through trial and error to correct for this.I may be wrong whether it kept the cables from touching the stab, which does not bother me, really, but I know pretty much everyone raises the bellcrank to some amount to lessen the rub, at least. Adding pulleys at the at end of the pilot seat makes it possible to raise it as much as necessary. I think the only reason Bernie's rubbed was that he avoided the use of pulleys.Thanks for the help, keep it coming, especially the source for the spring.Gene ----- Original Message -----
thanks to all for telling me to "build to the plans", and I think my airplane is probably closest to the plans of any I have seen, but I know that someone, maybe Ken Perkins, came up with a correction to the geometry of the bellcrank that eliminates the slack cables and keeps them the same tension throughout. At one time, I had made notes as to how it worked, but I cannot find them now. I do not think it was as simple as making the distance between the holes the same as on the elevator horns and stick controls, but it might have been. I think it had something to do with the bellcrank hinge not being in line with the holes for the cables, so there is some other measurement that works that someone arrived at through trial and error to correct for this.I may be wrong whether it kept the cables from touching the stab, which does not bother me, really, but I know pretty much everyone raises the bellcrank to some amount to lessen the rub, at least. Adding pulleys at the at end of the pilot seat makes it possible to raise it as much as necessary. I think the only reason Bernie's rubbed was that he avoided the use of pulleys.Thanks for the help, keep it coming, especially the source for the spring.Gene ----- Original Message -----
Pietenpol-List: help, please!
Original Posted By: "walt evans"
Pietenpol-List: help, please!
Original Posted By: John Egan
Re: Pietenpol-List: Wheel Strut Brackets
Original Posted By: Lars Hulgreen
Lars, I made my landing gear Vees out of 4 pieces of 1/4' ash laminated together (Cabanes also). To get size, angles etc I made a full size replica out of 1/4' pieces of foam board glued together. Jim Lagowski, NX221PT ----- Original Message -----
Lars, I made my landing gear Vees out of 4 pieces of 1/4' ash laminated together (Cabanes also). To get size, angles etc I made a full size replica out of 1/4' pieces of foam board glued together. Jim Lagowski, NX221PT ----- Original Message -----