Brodhead Pietenpol Association

Original Posted By: "Peter W Johnson"
Hey all,I have a question regarding the location of attachment of the flying strut. Iam building the three piece wing and am using 3/4" solid spars. Each half ofthe wing (not including the center section) is 13' 2.5" per plans. Today I laidout the spars and slid the ribs into position.As I read the plans, the center hole for the flying strut strap attachment to thespars is 79" from the root of the wing half. With my ribs in place, I measuredthis distance from the root of the wing. This location (79") appears tobe only 3/4" from the next (outer) rib. This doesn't seem to be correct as itdoesn't leave room for the underlying ply or the 3/4" square compression strutsthat would be fit in place.I did review westcoast piet pictures as well as some of the other personal buildsites (Textor, Markle, Chouinard) to see how others have done it, and none ofthe pictures I saw have the "spacing" problem I seem to be running into.I spaced my ribs according to Drawing No. 5 of the "Improved" plans (from the outeredge, 4.5, 12, 12.5, 12.5, 12.5, 12.5, 12", etc., moving towards the root).Moving the "offending" rib doesn't seem to be the answer as it will changethe aileron length.Did anyone else run into this problem? Or did I space my ribs incorrectly?Any advice would be appreciated.Thanks,TomRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Tom,I have just checked my photos and looks like I had a similar problem.This is how I solved it http://www.cpc-world.com/images/IMG_0964_JPG.jpgCheck out some more pictures at http://www.cpc-world.comCheersPeterWonthaggi Australia-----Original Message-----

Original Posted By: "K5YAC"
That is true on the disc brake-I'm a bike mechanic (until Monday-getting a new job!)and straight (or radial laced) wheels can't use a disc brake,the braking forces can pull the spokes from the hub.Actually hubs have to specifically designed for radial lacing becausethe extra tension required can also pull the flange off the hub.Radial laced wheels- with one set of spokes anyway- are also not as strong in side loads as cross laced wheels.--------Earl BrownI may not have gone where I intended to go, but I think I have ended up where Iintended to be.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Question Re: Flying Strut Attachment Location

Original Posted By: "Dortch, Steven D MAJ NG NG NGB"
Tom:I also used the rib spacing as called for in the plans, but if I recall correctly,I think I moved my fitting and other pieces of the assembly away from theribs in order to change the angle of the lift strut fitting (i.e. orient it inline with the lift strut as other builders have recommended). My lift strutswill attach several inches closer to the root because of the relocation, anglechange and the fact that I lengthened the fitting by about an inch. When Isay several inches closer, I mean about 4-5". This did create a bit of a clearanceproblem where the drag/anti-drag cables were concerned, which required modificationand reinforcement to several vertical or diagonal braces... I thinkseveral people have run into this problem. If I were to do it again, I would take the same approach, but I would probablymove the entire assembly (plywood backing, lift strut fitting, etc.) as closeas I reasonably could to the outer most rib, therefore placing the cable attachpoints and lift strut geometry closer to what is called for in the plans. The main drawbacks to how I did mine are, 1. The cables did not clear properlyand, 2. There is 4-5" more inches of wing beyond the lift strut attachment thanare in the original design.Hope this helps!--------Mark ChouinardWings, Center Section and Empannage framed up - Working on FuselageRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Tom,This may not help, as I used original drawings for the placement of my liftstrut brackets. Since the lift force is up, I have not understood thereasoning for aligning the brackets with the struts.Gary BootheNX308MB-----Original Message-----

Original Posted By: shad bell

Original Posted By: "tdudley(at)umn.edu"
I'm not sure if it makes a huge difference one way or another on the alignmentof the lift strut attach fittings... I got the idea from Chuck Gantzer's videosand it seemed like a reasonable idea to me, so I did mine that way. Not the greatest drawings, but for anyone that might wonder what we are talkingabout, the first illustration shows the orientation of the fitting accordingto the plans and the second illustration shows what Chuck recommends. I'm notsure that he recommended eliminating the top cap, as I did... his suggestionwas more about correcting the angle. If I recall, the idea that there may bea twisting motion applied to the fitting was undesirable. I've seen several examplesof both, probably not a big deal.--------Mark ChouinardWings, Center Section and Empannage framed up - Working on FuselageRead this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/lift ... ___Subject: Pietenpol-List: Question Re: Flying Strut Attachment Location

Original Posted By: Oscar Zuniga
I'd like to thank everyone for their reply to my question. It was somewhat reassuringto hear others have run into a similar situation; I was afraid I mighthave measured and spaced my ribs incorrectly.I think, after hearing the responses, I will probably keep the rib in its "perplans" position and modify its attachment such that the flying strut and its underlyingply will fit. I think I'd rather do this than move the lift strut fittingtowards the root and shorten the length of the lift strut.Peter, thank you for your quick response. Your website is one I've visited manytimes in the past (especially when I started my build--inspirational), and Ithink it is one of the best to re-visit.John, I've been following your build on the mykitplane.com. Let me know if youdiscover any hints or run into any snags in modifying your rib or placing yourlift strut.Mark, sorry if I "called you out" by mentioning you by name in my post, but yourbuild-web-site has been really helpful to me. I use it to "double-check" mywork.Gary, helpful advice and pictures as always.Thanks again,TomRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________

Original Posted By: owner-pietenpol-list-server(at)matronics.com
When I started building my wings, I looked at the odd attachment of the liftstrut fittings that were shown in the plans and started to redesign them tobe in line with the lift struts (as more moderne airplanes do), but first Idecided to do a stress analysis on the design. What I found surprised me,and gave me a lot more respect for Mr. Pietenpol as an engineer. His designputs a moment (a "twisting force") on the spar, which partially counteractsthe bending moment induced by lift along the span of the wing. The resultis that the stress within the spar is reduced slightly by using the designin the plans, so I left mine that way and did not change it. I'm glad I didn't change the design because I would have made the angle ofthe fitting wrong anyway, since long after I built the wing I decided tomake my cabanes taller than the plans show, which changed the angle the liftstrut makes with the spar anyway.Jack PhillipsNX899JPSmith Mountain Lake, Virginia-----Original Message-----

Original Posted By: "tdudley(at)umn.edu"
> --> Pietenpol-List message posted> by: "Clif Dawson" > > Ha! Now we're talkin! > Needs wheel pants to complete the scheme though.> > Clif> > > > Hey Clif,> > > > How about now?> > (although technically, it's a GN-1, rather than a> Piet)> > > > Bill C.> > > Email Forum -> - MATRONICS WEB FORUMS -> List Contribution Web Site -> -Matt> Dralle, List Admin.> > > > ________________________________________________________________________________Subject: Pietenpol-List: Question Re: Flying Strut Attachment Location