Brodhead Pietenpol Association

Original Posted By: "Graham Hansen"
Hello, low 'n' slow fliers-I think I may have mentioned this before, but here goes again. There is yet another alternative for your streamline tubing wing struts (or cabane struts, or any others). Say you want the strength of steel with welded fittings but don't want to pay for streamline tubing. Well, build your struts out of plain round 4130 tube. Make the ends anything you want... fishmouth into plates, flatten the ends and drill for bolting, weld in adjustable clevis fittings, however you want to do it, using round tubing, then get some of the extruded, paintable plastic streamline fairings that the ultralight/light plane guys use. It slips on over the tubing. Cuts easily, you can shape the ends anyway you want to make them fit your ends, and you can glue the ends or other pieces together to fit your needs.One source is Stream-Line in North Port, FL; email streamlineco(at)yahoo.com and website is at http://streamline.8k.com/ they have a set of four, 8' sections of their "small" fairing material (fits up to 1-1/4" dia. round tubing) for about $170, or about $5.31 per foot.Like I said; it's just one more way to skin the cat. Maybe not for everybody, but some expressed hesitancy at using aluminum extrusions for this application, so go ahead and use steel... but streamline it.Oscar ZunigaMedford, Oregonmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________

Original Posted By: Oscar Zuniga
or you could use round tubing and streamline it with balsa, which is exactlywhat I would do if I didn't have these Cub struts.----- Original Message -----

Original Posted By: "Greg Cardinal"

Original Posted By: "Gene Rambo"
would you use 1-1/4" 4130 for both struts?----- Original Message -----

Original Posted By: "Jack Phillips"
Oscar Zuniga pointed out:> then get some of the extruded, paintable plastic streamline fairings that> the ultralight/light plane guys use. It slips on over the tubing.As yet another alternative, a friend who was building a Heath Parasoldid pretty much the same thing by gluing rigid foam to the tubing,sanding it to shape, and wrapping it in the thin, coarse fiberglass usedthese days as joint tape in hanging drywall. (There are two types; heused the one without its own adhesive.) Finally, he slathered on athin layer of epoxy. Stiffened things up amazingly, without addingmuch weight.Owen Davies---Checked by AVG anti-virus system (http://www.grisoft.com).________________________________________________________________________________

Original Posted By: owner-pietenpol-list-server(at)matronics.com
The only concern I would have about the use of round tubing with astreamlined fairing over it is rust. My brother recently recovered hisCitabria, and the only places he found rust were where fabric was glued tothe steel tubing. Invariably, at each of those locations there was somerust, and occasional pitting. I don't know what kind of primer ChampionAircraft used in the '70's when this plane was built, but it wasn'tadequate.I would strongly recommend a very good (read, expensive) epoxy primer on anysteel strut that will have a cover glued to it, because you will not be ableto inspect the condition of the steel after it is assembled. A failure of alift strut due to corrosion will ruin your whole day.BTW, on my Piet I have used Randolph Epibond epoxy primer, and StitsPolyFiber epoxy primer. The PolyFiber is far superior, and can only beremoved by sandblasting once it is cured. I've had some of the Randolphprimer wear off the centersection fittings, just due to assembling anddis-assembling the wings a few times.Jack -----Original Message-----

Original Posted By: "Greg Cardinal"

Original Posted By: "Greg Cardinal"
I've done the math... and to quickly sum it up, the aluminum streamlinetubing from Carlson is plenty strong. As for round 4130, I haven't run thenumbers, but would see no reason why it wouldn't work assuming it'sequivalent of streamline was used. The AS&S catalog shows 4130 streamlinetubing and it's round equivalent.The other thing to consider is under normal circumstances the Piet willprobably never get going fast enough to break much. It'll likely stallbefore you can load the structure enough to break anything..... again,under normal circumstances.Which brings me to a question. I've done some searching through the NTSBaccident investigation archives and so far I've found about 7 accidents inthe past 10 years involving Piets or GN-1's. In each case it was enginefailure and one was a severe ground loop. None were due to structuralfailure. I haven't searched the archives in a thorough manner, but it seemsthat the only time you'll get hurt in a Piet is if your engine dies. hmmmmsuppose it's a good thing I'm going with a certified aero engine and notsomething meant for 4 landlubberly wheels anyhow, my question is... has anyone ever heard of a case where a Piet wentdown due to catastrophic structural failure?DJ VeghMesa, AZGN-1 Builderwww.raptoronline.comN74DVAll well and good, a bunch of alternatives, but has anyone done the mathfor the appropriate size round steal or aluminum tubing?Eyeballing the size and thickness doesn't cut much mustard when you'redealing with the critical load bearing structure.Larry________________________________________________________________________________Date: Tue, 12 Mar 2002 10:25:29 -0600

Original Posted By: "Steve Eldredge"

Original Posted By: Michael D Cuy
Steve,Good to see your name pop up. There are those of us who need to know that thoseof you who paved the way are still as enthusiastic.Larry Ragan Jacksonville, Fl. lragan(at)hotmail.com ________________________________________________________________________________Date: Tue, 12 Mar 2002 12:28:50 -0500

Original Posted By: del magsam

Original Posted By: Isablcorky(at)aol.com
you bet.... it's www.sky-tek.com I ordered my struts from them lastweek. Should get here in the next couple days. When they do I'll snapsome pics and post them to my site and let you all know how they look.DJwww.raptoronline.com----- Original Message -----Pietenpol-List message posted by: Dean Pacetti >> V.J.> I have for some reason, unknown to even myself,> deleted the Carlson address from my puter and now I> can't find it. Would you mind posting it again for me.> And I promise to bookmark it this time :-}}> Thanks> Dean Auburndale, Fla.________________________________________________________________________________

Original Posted By: john e fay
Subject: Pietenpol-List: Sheet MetalPieters,I am beginning an area which is totally new to me. In all my years and many endevors I have never been exposed to sheet metal work lest it be to cover the barn or shed with the corrugated stuff. Thanks for the Mike Cuy help and guidance I have completed my nose bowl in .025 Alum. NOW my concern and question to the list IS: May or can I use .020 Alum for the four pieces of cowling and expect it to be ridged enough? I have a bunch which I got cheap and would like to use it but not at the expense of something unsatisfactory. This cowl is for the A-65 engine cantilevered from the firewall bulkhead.Corky in La________________________________________________________________________________Date: Tue, 12 Mar 2002 12:37:04 -0600Subject: Re: Pietenpol-List: streamline tubing

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Hi Corky,You and I are in the same boat. I'm pretty fair with the woodwork, and thewelding, but I'm now making the cowlings or coamings or whatever you callthe sheetmetal aft of the firewall that covers the top of the fuselage. I'mhaving to learn all kinds of new skills.I'm using .025" Alclad 2024-T3 material, primarily because my brother had abunch left over from his Hatz Biplane project and gave it to me. I suspectthat .005" difference in thickness might be noticeable, but probablywouldn't be catastrophic. If it is, you could always rivet some ribs ordoublers on the inside to stiffen it up a little. Home Depot sells somevery nice 1/2" x1/2" x .050" aluminum angle that could be riveted inside thecowling (running parallel to the curvature) to add quite a bit of stiffness.I'm using some of that to stiffen up the skin around the baggage door I'mmaking for the comaprtment forward of the front cockpit (my fuel tank is inthe centersection). It's light, it's stiff and it's cheap. I bought an 8'piece of it this morning for $3 and some change.I'd go ahead and use what you've got, assuming it's not some dead-softaluminum. If it's 2024-T3 or 6061-T6 it is probably fine. Like I said, ifit is too flimsy, you can always add a few stiffeners for a whole lot lessmoney than buying another sheet of aluminum.Jack -----Original Message-----

Original Posted By: Doug413(at)aol.com
Subject: Re: Pietenpol-List: Sheet MetalThanks Jack,You said what I wanted to hear. I failed to mention that I'm really enjoying this sheet metal work as you can see your results so soon.Corky in cold La________________________________________________________________________________

Original Posted By: Michael D Cuy

Original Posted By: Isablcorky(at)aol.com
----- Original Message -----

Original Posted By: Dean Pacetti

Original Posted By: Larry Neal

Original Posted By: Mark
personally, whatever I did I'd make all four the same. I have not thoughtthrough what diameter round I would use, but 1 1/4 sounds about right.----- Original Message -----

Original Posted By: Larry Neal