Original Posted By: Matt Dralle
Subject: Pietenpol-List: one piece wingPieters, For my one piece wing I am getting ready to glue my spars together - as per the Pietenpol plans. Has anyone had any problem with this glue joint or flack from the FAA inspectors? Anyone have special tips or cautions?------thanksHenry Williams________________________________________________________________________________Date: Fri, 22 Nov 2002 02:02:18 -0800
Pietenpol-List: one piece wing
RE: Pietenpol-List: one piece wing
Original Posted By: "Kent Hallsten"
RE: Pietenpol-List: one piece wing
Original Posted By: "walter evans"
Henry,The center scarf joint that BHP shows doesn't even come close to the 1:12slope required for a "real" splice. But it's a lot easier to cut. Thereason he got away with it is that the wing is in essentially purecompression at that point--there's no bending moment at all. That's why wecan get away with the 3-piece wing with no change to the struts. Do thestress analysis--it's interesting and straight out of Freshman Physics.________________________________________________________________________________
Henry,The center scarf joint that BHP shows doesn't even come close to the 1:12slope required for a "real" splice. But it's a lot easier to cut. Thereason he got away with it is that the wing is in essentially purecompression at that point--there's no bending moment at all. That's why wecan get away with the 3-piece wing with no change to the struts. Do thestress analysis--it's interesting and straight out of Freshman Physics.________________________________________________________________________________
Re: Pietenpol-List: one piece wing
Original Posted By: "Hubbard, Eugene"
I disagree with your statement about no bending moment at the centerline.If you will, imagine the left wing wanting to rotate around the left cabane,and the right wing wanting to rotate around the right cabane. Now sketchout an exagerated version of it and you will notice that a lot of curvaturewill be required to connect the lines for the left and right sides. If thatdeformation is constrained a moment will result. The one piece wingobviously constrains that.There are several very simple solutions. You could rotate the plane of thesplice 90 deg as suggested in the builders manual. Or you could build thewing like BHP did his last few from several pieces of wood laminatedtogether. I plan on going with laminations as that will allow a gentleslope at each interface. Even better is the fact that smaller pieces ofwood are more easily gotten, shipped and I could make that up out of 12 ftsticks. It also has built in 'crack stoppers'. Stagger the splices so theyare not at the same location and such that they are not at a fitting either.I would put the cap splices at the least bending location, which issomewhere outboard of the center section (sketch it out with exagerateddeflections, or play with some thin balsa stock until you get the idea.) Asfor why so many have successfully flown with the rather awkward splice shownin the original plans (and bolts at the same location that removecross-sectional area from the spar where it is needed most) is easilyexplained by the 'rugged construction.' If things are stout enough they donot have to be ideal. That splice is just about the only area where in myopinion the design as drawn on the plans is not very well thought out. Thegood news is that it is easily cured. Whatever you do keep it simple andlight. The three piece wing does not suffer from that shortfall, however itpays for that with 30 lbs and a lot of extra effort.Kevinhttp://www.angelfire.com/va2/aerodrome/----- Original Message -----
I disagree with your statement about no bending moment at the centerline.If you will, imagine the left wing wanting to rotate around the left cabane,and the right wing wanting to rotate around the right cabane. Now sketchout an exagerated version of it and you will notice that a lot of curvaturewill be required to connect the lines for the left and right sides. If thatdeformation is constrained a moment will result. The one piece wingobviously constrains that.There are several very simple solutions. You could rotate the plane of thesplice 90 deg as suggested in the builders manual. Or you could build thewing like BHP did his last few from several pieces of wood laminatedtogether. I plan on going with laminations as that will allow a gentleslope at each interface. Even better is the fact that smaller pieces ofwood are more easily gotten, shipped and I could make that up out of 12 ftsticks. It also has built in 'crack stoppers'. Stagger the splices so theyare not at the same location and such that they are not at a fitting either.I would put the cap splices at the least bending location, which issomewhere outboard of the center section (sketch it out with exagerateddeflections, or play with some thin balsa stock until you get the idea.) Asfor why so many have successfully flown with the rather awkward splice shownin the original plans (and bolts at the same location that removecross-sectional area from the spar where it is needed most) is easilyexplained by the 'rugged construction.' If things are stout enough they donot have to be ideal. That splice is just about the only area where in myopinion the design as drawn on the plans is not very well thought out. Thegood news is that it is easily cured. Whatever you do keep it simple andlight. The three piece wing does not suffer from that shortfall, however itpays for that with 30 lbs and a lot of extra effort.Kevinhttp://www.angelfire.com/va2/aerodrome/----- Original Message -----
RE: Pietenpol-List: one piece wing
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Years ago I did a simple stress analysis of the three piece wing. What Ifound was that with the lift struts at almost the exact center of the wingpanels, they carried virtually all the lift loads. The vertical loads atthe bolts that attach the outer panels to the centersection are about 6 lbseach. Of course, the spanwise loads are quite large, tending to push theouter panels into the centersection. I agree with Gene, the loads in thecenter of the centersection are pretty small, but if I built a one oiecewing I would still orient the scarf joint as shown in AC 43.13. The factthat BHP was able to get away with his original joints indicates how low theloading is in that portion of the spar.Jack Phillips -----Original Message-----
Years ago I did a simple stress analysis of the three piece wing. What Ifound was that with the lift struts at almost the exact center of the wingpanels, they carried virtually all the lift loads. The vertical loads atthe bolts that attach the outer panels to the centersection are about 6 lbseach. Of course, the spanwise loads are quite large, tending to push theouter panels into the centersection. I agree with Gene, the loads in thecenter of the centersection are pretty small, but if I built a one oiecewing I would still orient the scarf joint as shown in AC 43.13. The factthat BHP was able to get away with his original joints indicates how low theloading is in that portion of the spar.Jack Phillips -----Original Message-----
Re: Pietenpol-List: one piece wing
Original Posted By: Mike Hardaway
Subject: Re: Pietenpol-List: one piece wingI agree with almost everyone else one this wing splice. Use the method in the 43.13 it is much stronger than that shown on the plans. I have also seen the building manual and it says to use the 43.13 method. Just remember in the 30's not a lot of information was available about aircraft construction, I don't even think the old CAM 18 manuals were around, which was the equivalent of the today's 43.13. Pietenpol was a brilliant eyeball engineer, who had a moderate education, in my opinion his plans leave a lot to be desired for the novice builder. Dan ________________________________________________________________________________Date: Fri, 22 Nov 2002 21:13:39 -0800
Subject: Re: Pietenpol-List: one piece wingI agree with almost everyone else one this wing splice. Use the method in the 43.13 it is much stronger than that shown on the plans. I have also seen the building manual and it says to use the 43.13 method. Just remember in the 30's not a lot of information was available about aircraft construction, I don't even think the old CAM 18 manuals were around, which was the equivalent of the today's 43.13. Pietenpol was a brilliant eyeball engineer, who had a moderate education, in my opinion his plans leave a lot to be desired for the novice builder. Dan ________________________________________________________________________________Date: Fri, 22 Nov 2002 21:13:39 -0800
Pietenpol-List: one piece wing
Original Posted By: "Richard Schreiber"
I need to talk to anyone who has built, or is building, a one piece wing. Please contact me offline and I will exchange phone numbers so we can talk a bit. Gene ________________________________________________________________________________
I need to talk to anyone who has built, or is building, a one piece wing. Please contact me offline and I will exchange phone numbers so we can talk a bit. Gene ________________________________________________________________________________
Re: Pietenpol-List: one piece wing
Original Posted By: Gene Rambo
GeneI have built both the one and three piece wing. Your e mail address didnt appear on your post. You can mail me back at horzpool(at)goldengate.net Dick N. ----- Original Message -----
GeneI have built both the one and three piece wing. Your e mail address didnt appear on your post. You can mail me back at horzpool(at)goldengate.net Dick N. ----- Original Message -----