Original Posted By: "Greg Cardinal"
Subject: Pietenpol-List: end ribs' extra bracingPieters,On my piet plans (drawn by Hoopman) on the rib sheet it is noted to use 5 extra braces on 2 end ribs only. I take this to mean the extra braces are used on the left end rib and on the right end rib. Two ribs with the extra treatment. (( But it might mean extra braces on the 2 end ribs on the left and the 2 end ribs on the right --- that would be 4 ribs with the extra treatment. )) Can someone in the know put me straight on this?thanksHenry Williams (Borodent)________________________________________________________________________________Date: Wed, 27 Mar 2002 07:11:02 -0600
Pietenpol-List: end ribs' extra bracing
Re: Pietenpol-List: end ribs' extra bracing
Original Posted By: "Hubbard, Eugene"
Subject: Re: Pietenpol-List: end ribs' extra bracingThe extra braced ribs are also used on the inner ends of the three piecewing aren't they? They are stiffer to help stop the fabric from pullingthem out of shape. The plans only address the one piece wing. thats whythey only call for two. I even used extra braced ribs on the ends of mycenter section for a total of six. But then I'm no Piet expert . Howabout some more input. Ed________________________________________________________________________________
Subject: Re: Pietenpol-List: end ribs' extra bracingThe extra braced ribs are also used on the inner ends of the three piecewing aren't they? They are stiffer to help stop the fabric from pullingthem out of shape. The plans only address the one piece wing. thats whythey only call for two. I even used extra braced ribs on the ends of mycenter section for a total of six. But then I'm no Piet expert . Howabout some more input. Ed________________________________________________________________________________
RE: Pietenpol-List: end ribs' extra bracing
Original Posted By: flyboy_120(at)webtv.net [mailto:flyboy_120(at)webtv.net]
No reason for extra vertical bracing on the inboard ribs--the fabric isn'tpulling in that direction. I had to do quite a bit of rework to get spacefor the root fitting bolts even without the extra structure. That said, Iknow that some people put a solid 1/16 plywood web on the inboard rib.Gene HubbardSan Diego-----Original Message-----
No reason for extra vertical bracing on the inboard ribs--the fabric isn'tpulling in that direction. I had to do quite a bit of rework to get spacefor the root fitting bolts even without the extra structure. That said, Iknow that some people put a solid 1/16 plywood web on the inboard rib.Gene HubbardSan Diego-----Original Message-----
Re: Pietenpol-List: end ribs' extra bracing
Original Posted By:
I used the added bracing rib on the last out on the ends before bow, and onboth sides of the joint of the three piece wing. ( that would be a total of6) Also did the 2"wide ply, and the 1/2X1/2 diagonal bracing called out onthe three piece wing print.OR in other words, built to the print. Covered the second wing in the lastfew weeks, with absolutely no distortion at all.Once you start to tighten and start to get distortion, you're screwed.walt----- Original Message -----
I used the added bracing rib on the last out on the ends before bow, and onboth sides of the joint of the three piece wing. ( that would be a total of6) Also did the 2"wide ply, and the 1/2X1/2 diagonal bracing called out onthe three piece wing print.OR in other words, built to the print. Covered the second wing in the lastfew weeks, with absolutely no distortion at all.Once you start to tighten and start to get distortion, you're screwed.walt----- Original Message -----
Re: Pietenpol-List: end ribs' extra bracing
Original Posted By: "Jack Phillips"
I built my three piece wing with the extra bracing on six ribs:the tip ribs, the butt ribs and the center section ribs.There has never been a problem with the tip ribs, but fabrictension has distorted the butt ribs in a spanwise direction de-spite the extra bracing I provided (similar to that used by Pi-per and others). The center section ribs have bowed in a bit,but not as much as the butt ribs. I think I have in my Pietenpol a good example for a longevitytest at close to 32 years, and my experience may be of help to others. Today's builders will likely not have my distortion problem because I used butyrate dope which tends to continue shrinking over time, imposing loads which will distort a light structure such as a rib. Modern finishes don't have the tauten-ing feature of dope and, with synthetic fabric, the proper ten-sion is established by heat shrinking.One thing I have noticed with elderly Pietenpols is that the toprib capstrip tends flatten and lose its curvature between thegusseted joints. The span between these in the Warren-typerib truss is a bit too great. The fix, which I have used at recover-ing time, is to install a nearly-vertical 1/2" x 1/4" spruce member with the lower end epoxied in the gusset pocket of the lower cap-strip. The upper end is simply epoxied to the underside of the upper capstrip with a single 1/2" nail to hold it in place while the epoxy cures. Only two of these per rib are required and they aremost effective, adding very little weight. If you look at the Pieten-pol rib truss, you will get the picture. The three old Piets in ourarea that I have dealt with (built in 1967, 1970 and 1975) haveall had this problem. When I get around to recovering mine, I'llhave to deal with it in the manner described above. Graham Hansen Pietenpol CF-AUN________________________________________________________________________________
I built my three piece wing with the extra bracing on six ribs:the tip ribs, the butt ribs and the center section ribs.There has never been a problem with the tip ribs, but fabrictension has distorted the butt ribs in a spanwise direction de-spite the extra bracing I provided (similar to that used by Pi-per and others). The center section ribs have bowed in a bit,but not as much as the butt ribs. I think I have in my Pietenpol a good example for a longevitytest at close to 32 years, and my experience may be of help to others. Today's builders will likely not have my distortion problem because I used butyrate dope which tends to continue shrinking over time, imposing loads which will distort a light structure such as a rib. Modern finishes don't have the tauten-ing feature of dope and, with synthetic fabric, the proper ten-sion is established by heat shrinking.One thing I have noticed with elderly Pietenpols is that the toprib capstrip tends flatten and lose its curvature between thegusseted joints. The span between these in the Warren-typerib truss is a bit too great. The fix, which I have used at recover-ing time, is to install a nearly-vertical 1/2" x 1/4" spruce member with the lower end epoxied in the gusset pocket of the lower cap-strip. The upper end is simply epoxied to the underside of the upper capstrip with a single 1/2" nail to hold it in place while the epoxy cures. Only two of these per rib are required and they aremost effective, adding very little weight. If you look at the Pieten-pol rib truss, you will get the picture. The three old Piets in ourarea that I have dealt with (built in 1967, 1970 and 1975) haveall had this problem. When I get around to recovering mine, I'llhave to deal with it in the manner described above. Graham Hansen Pietenpol CF-AUN________________________________________________________________________________
RE: Pietenpol-List: end ribs' extra bracing
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Thanks, Graham,Good information to have, from an authority who can speak from experience.I wonder if the newer polyester fabrics finished without tautening dope willexhibit this problem?Thanks for the input.Jack -----Original Message-----
Thanks, Graham,Good information to have, from an authority who can speak from experience.I wonder if the newer polyester fabrics finished without tautening dope willexhibit this problem?Thanks for the input.Jack -----Original Message-----
Re: Pietenpol-List: end ribs' extra bracing
Original Posted By: "Hubbard, Eugene"
I used 1/8" ply on my inboard ribs and still got a 1/4" distortion when thefabric was totally streched. I have a one oiece wing. I solved the problemby installing two threaded rods to tie the ribs together. I used a #4 x 40x 36" stainless rod with a small oak backing plate to draw the ribs backtogether, They only weigh a couple of ounces and fit above the fuel tank.Dick----- Original Message -----
I used 1/8" ply on my inboard ribs and still got a 1/4" distortion when thefabric was totally streched. I have a one oiece wing. I solved the problemby installing two threaded rods to tie the ribs together. I used a #4 x 40x 36" stainless rod with a small oak backing plate to draw the ribs backtogether, They only weigh a couple of ounces and fit above the fuel tank.Dick----- Original Message -----
RE: Pietenpol-List: end ribs' extra bracing
Original Posted By: Richard Navratril [mailto:horzpool(at)goldengate.net]
Are you talking about spanwise or vertically? For spanwise bracing on my3-piece wing, I have every piece of bracing that I could find on the plans.Gene-----Original Message-----
Are you talking about spanwise or vertically? For spanwise bracing on my3-piece wing, I have every piece of bracing that I could find on the plans.Gene-----Original Message-----
Re: Pietenpol-List: end ribs' extra bracing
Original Posted By: "Hubbard, Eugene"
The tops of both inboard ribs pulled out towards the tips. The bottoms areheld in place by the plywood bottom of the fuel tank base.Dick----- Original Message -----
The tops of both inboard ribs pulled out towards the tips. The bottoms areheld in place by the plywood bottom of the fuel tank base.Dick----- Original Message -----