Brodhead Pietenpol Association

Original Posted By: "montanacos"
Douwe,I remember a discussion about this from about a year ago, so I looked up aposting I made back then. Here it is:The most likely reason for choosing aluminum over stainless steel isweight. On a volumetric basis, stainless steel weighs almost 3 times asmuch as aluminum. The typical aluminum tank seems to be made from .040"thick aluminum. This thickness can be TIG welded successfully (by askilled welder) to produce a leak-proof tank. The thinnest stainlesssteel that can practically be welded (again, by a skilled TIG welder) isprobably 22ga (.031" thick) or 20ga (.037").Without doing any accurate calculations, it looks like the typical nosetank (like Mike Cuy's sketch) might have about 20 square feet ofsurface. Aluminum weighs .563 pounds per square foot for .040"thickness, and T304 stainless steel weighs 1.27 pounds per sq.ft. for.031" thickness. The aluminum tank would weigh about 11 pounds, whereasthe stainless tank would weigh about 25 1/2 pounds. That's a 14+ poundpenalty. (If you choose 20ga st.st. add an additional 5 pounds.)So, to answer your question directly, the thinnest gauge that is weldable bythe average skilled welder of stainless steel is probably 20ga. That willprobably be the limiting factor.Whether you want an extra 20 pounds in your plane is another question.Bill________________________________________________________________________________Subject: Pietenpol-List: Finished wieghts of Spruce Piets vs. Douglas Fir Piets

Original Posted By: "bhassel"
I have followed this site for years, and have been wanting to start building anairplane with a corvair engine for a long time. I posted several years ago afterfinishing a house and was hoping to start building soon. Well, plans getpushed back, and I built another house weekends and evenings and still am hopingto start building something fun. Of course, I have a young family and moneyis an issue. I have not been blessed with a pilots build however. I am about 255 lbs, and withdiet and exercise, I could comfortably loose 15 to 20 lbs. So I am nevergoing to be the 140 lbs that makes flying a small airplane with a passenger niceand easy. Building material weight is also an issue. I need to build light,but if I can compromise a little on weight, then maybe I can afford to getin the air on my limited budget. My question is on the finished weights of two similar Piet's, one of spruce, andone of douglas fir. I have a brother who works at a planer here in Montanaand they get lots of douglas fir. He said that he could set aside the nice verticalgrain fir if I am interested. This would significantly cut down on thecost, and I would be able to start the construction as soon as I purchase theplans. I have the Flying and Glider Manual that covers the Piet, and have thoughtof drawing the rib on autocad and building the ribs until I purchase thecomplete set of drawings including the long fuse for the corvair engine. I don'tthink there would be any copy right issues with that approach since the informationI have comes from the Flying and gliders manual. Thanks in advance and I hope to start soon.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: visitors welcome and Brodhead

Original Posted By:> montanacos
The Flying and Glider is great to look over the plans and see how things gotogether, but there are alot of differences between the F & G and the 1934plans. There are minor differences in the dems of the wing profile andmajor differences in the fuse and tail feathers. Take it from someone whofound out the hard way, better to not the mix plans.Skip> [Original Message]

Original Posted By: Isablcorky(at)aol.com
Thanks for the advise on waiting until I have the plans. I certainly don't wantto waste time and money. Just the kind of input that I am looking for.Have a good dayTimRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________