Tube construction: Alternatives to conventional welding

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Little Scrapper

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:roll:

I generally do not think it is a question of easy that is the issue. Anyone who takes on the task of building an airplane and finishes it deserves kudo's in my book.
However, I am realistic (I hope). If things go well financially, I am looking to purchase a kit late next year. Reason for a kit versus plans is because of time. I would like to have a working plane before I retire.
This is why I am following/interested in your other thread on build processes you are attempting with the new plane.

Tim
This right here.

You are a 100% correct. Many people, including myself, are battling time. I have a full set of full size WACO plans, I also have the money to build it. I love building from scratch. It probably will never happen.

The Cassutt is dead simple in every possible way and I still am in a serious struggle to build it. Life, you know.

Although I'm a die hard scratch guy I totally understand the quick build option coupled with a very complete and dumbed down kit.

I watched 2 friends build a RV9A and 7 friends build a Sonex. The RV was completed in 4 years and after 12 years still waiting on 6 of the 7 Sonex to get finished.

Some people are ok with building and never flying. I'm like you, I wanna finish it and fly it.

Until a airplane is flying it's not really a airplane, it's a pile of scrap. And I agree, to actually finish it and fly it is a monumental achievement even for the easiest of kits.

When people comment that I'm building a Cassutt I correct them and so no, I'm TRYING to build a Cassutt.
 

dcstrng

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:roll:
Reason for a kit versus plans is because of time. I would like to have a working plane before I retire.
Me too -- and I finally figured out how to achieve it; just keep pushing your retirement date out (nope, not kidding -- at least not much)
 

Vigilant1

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I think everyone is in agreement that nobody has any business building a plane if they don't enjoy the building process. If the building isn't fun/enjoyable/rewarding then they should be building something else that they'd enjoy working on, or just buy a plane and fly it.

Luckily, there are plenty of existing designs and construction methods so there's a good likelihood most people who want to build from plans or a kit can find something existing. But just as there are people who enjoy welding, there are people who enjoy devising new ways to build things. Designing/trying/testing a new technique is a lot riskier and will take a lot more time (and probably money) than doing something in a proven way, but if person enjoys the process, that's not necessarily a negative thing.
 

gtae07

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Go to the NASM on the capital mall or any of the several other museums around and look at the Apollo modules. Lots of riveted aluminum. Why? Riveted aluminum for many loads is light for the strength. If you welded the aluminum alloy parts, you lose the high strength temper it arrived with, and while most alloys will regain some of its strength, you will still end up having to design with either larger tubes or bigger thicknesses or both, giving back much or all of the weight save.
High-end aerospace manufacturing is increasingly moving towards the use of machined parts over built-up formed and riveted sheetmetal assemblies. A fuselage frame that might have been back-to-back ribs riveted together with doublers and stiffeners is now one machined part. A cockpit canopy structure (not fighter canopy, but the area above/behind the windscreen on something like an airliner) that used to be made from built-up frames and skin may now be a single machined/forged frame with a skin, or just a single machined forging. I've seen proposals for things like gear doors, spoilers, and baggage doors to be single monolithic machinings. The same probably holds true on the new generation of spacecraft--what was a riveted skin panel segment on Apollo is likely a single aluminum machining with integral stiffeners on something like a Dragon. At least, that seems to be the case based on PR photos released by SpaceX. This approach (large machinings) is favored now for a few reasons; it reduces overall production cost because it requires fewer expensive man-hours for fabrication and assembly, parts require less jigging and fitting, and fewer specialized tools like sheetmetal forms and presses, dies, etc. are required (and the expensive do-all CNC machines can still get amortized over development and fall under the "invested capital" portion of the budget). You also get some good weight savings in some situations, and to a point, fewer places for stress concentrations (i.e. fastener holes).

The downside of that approach is that such structures can present some interesting repair challenges. You can't easily just slap doublers in place or drill out and replace a few sheetmetal components.

Additive manufacturing is the next wave of this, though it's not mature enough for use in all but a few select applications.
 

Swampyankee

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Go to the NASM on the capital mall or any of the several other museums around and look at the Apollo modules. Lots of riveted aluminum. Why? Riveted aluminum for many loads is light for the strength. If you welded the aluminum alloy parts, you lose the high strength temper it arrived with, and while most alloys will regain some of its strength, you will still end up having to design with either larger tubes or bigger thicknesses or both, giving back much or all of the weight save.

Billski
On the other hand, welded aluminum aircraft have been built -- the OS2U was largely spot-welded, vs riveted.
 

BBerson

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Spot welded aluminum sheet is used in factories, but needs an expensive spot welder, I think.
I haven't seen any welded aluminum tube commercial certified airplanes. I have seen a few ultralights using 6061-t6 welded tube.

Commercial boats are largely welded with 5083 plate, I think. Interestingly, I noticed that 5083-O is much stronger than 6061-O.
This suggests that 5083 might also have a higher post weld strength.
5083-O is 35ksi ultimate tensile. (18ksi compression)
6061-O is 16ksi ultimate tensile. (6ksi compression)

I don't know if 5083 tube is available.?
 

cheapracer

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On the other hand, welded aluminum aircraft have been built -- the OS2U was largely spot-welded, vs riveted.
Ford have gone to horrendous expense for a new process to spot weld aluminium just recently while GM, to Ford's embarrassment, have discovered a simple low cost method.

I did read about it a month or so back, try Google.

As many know, car companies are turning to aluminium in a big way as more and more percentage of a car manufactured needing to be recycled come into law. Germany is something like 90% now.

BB, I think 5000 series is used because of the sea water corrosion factor, not 100% sure.
 

WonderousMountain

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5053 isn't bad, corrosion resistance is a good part of why it's used in boats.
It's fairly strong and welds readily. Also it's a good deal less costly.

Not a good substitute for structural, but if you're going to use a heat treat alloy, don't get the 0 condition.
One number can make a helluva lot of difference.
 

wsimpso1

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Builders build a Vans and fly it having built nothing previously in their lives, how?
Van's airplanes are sheet metal riveted together, all of the steel structures come to you welded and powder coated, ready for retaining pins and bolts, and I can not remember any welded aluminum parts, but if there are any, they come welded and ready to go too.

Billski
 

wsimpso1

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After being around boats for decades I always thought I loved to work with nice, friendly, good-natured, forgiving wood – right up until I built a dozen ribs for the Buttercup and grew to detest it, yuck...
I built whole set of buttercup ribs and liked the process, just shows you personal taste in processes... and I just love welding now too. Sheetmetal work and riveting, well, I do not think there is a bird out there where you will not have some of it, but I would never complete a metal bird, again showing personal taste in processes. This why I make such a big deal out of telling folks to select a material set you love working in, and then selecting a project that uses them to build in. If you want to build in welded and pop riveted aluminum, I hope that you can find it. If you want to design in the stuff for marketing reasons, have fun and I hope you can find enough customers.

Billski
 

wsimpso1

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What you have to realize is that you CAN do it if you will make an honest attempt.

Here are some O/A welds from some Bearhawks that have been flying for years. The builders are well known. At least one has written and been published.

View attachment 60572 View attachment 60573 View attachment 60574 View attachment 60575

Weld something, put it in a vise and saw it in two and check penetration. Then weld something else, put it in a vise and try to knock it apart with a hammer. Then worry about how beautiful your weld is.
Not the prettiest welds on the planet, but they work! The welds are stronger than the neighboring base metal, and anyone with these welds in a flying airplane has nothing to be ashamed of and everything to be proud of.

Billski
 

dcstrng

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I built whole set of buttercup ribs and liked the process, just shows you personal taste in processes... This why I make such a big deal out of telling folks to select a material set you love working in, and then selecting a project that uses them to build in.

Billski
Yep... I think you are absolutely right -- I find that builders and aircraft that don't especially like each other, eventually end up finding ways to ignore each other... There is nothing wrong with the Buttercup wings (only this weekend hack), and I was surprised to find that wood and I weren't best-buddies anymore... By comparison, hammering out metal ribs (which is more brute force and less art I suppose) seems to satisfy my need for instant gratification or something...

I was able to find a salvage fuselage, so I didn't have to weld up that from scratch -- but different tankage, the addition of flaps and engine rotation opposite the original Lycoming and those piddly things scratch-builders inevitably feel they "must have," have afforded many (usually) happy hours sniffing acetylene and argon...
 

PTAirco

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Also anyone who thinks this is the bee's knees should go look at a few steel frame build blogs, the amount of time just for the frame and welding. The times are actually listed in this one ..

http://www.homebuiltairplanes.com/forums/showthread.php?t=20841&page=4

I've built numerous cars, car chassis and roll bars from mild steel with welding without any real regard to quality assurance and metal considerations that aircraft need, and I've spent a lot of time now gusseting and riveting, no contest which is easier and faster for the homebuilder. Gussets and rivets for the win.

Uhm. I've built a basic welded steel tube fuselage for a biplane in about 8 days. Fully welded. I'll race you, cheapracer.
 

cheapracer

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Uhm. I've built a basic welded steel tube fuselage for a biplane in about 8 days. Fully welded. I'll race you, cheapracer.
Well 8 hours is pretty good going.

Wait, 8 days? 8 DAYS?? :shock:

Ok, jokes aside, 8 days is admirable for a welded frame, you obviously have the tools and skillsets required, well done, but few are in your shoes.

I gave you an example, there are many more out there where the welded system appears to take people a long time, but then again so do pre-matched hole Vans builds. I weld my own car chassis, even with 'fast build' systems I developed with those it is still a slow and somewhat demanding process, especially if jigless.

You can not compete in time with my system, period. I would be at around a 1/3rd of that time, 2 - 3 days, no skillsets or special tools required.

I don't think it matters though, people seem to be pre-set in which method they are going to choose.
 

Little Scrapper

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Measure build time in days is irrelevant. 1 hour a day? 14 hours a day?

It does make me wonder about something. In the old Sport Aviation magazine there's many examples of builders pounding out airplane in a few months start to finish. I wonder why?

Even kit assemblers with these aluminum pre punched kits take years. Many scratch built steel airplanes take years also but many many are done in a matter of months, so it's irrelevant. I've read about Thorp builders scratch building them in under 6 months.

In the old days they didn't have distractions I suppose. Things like the Internet, mobile devices etc. People watched less tv I'd imagine. There's probably a lesson in here somewhere.
 

gtae07

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Measure build time in days is irrelevant. 1 hour a day? 14 hours a day?

It does make me wonder about something. In the old Sport Aviation magazine there's many examples of builders pounding out airplane in a few months start to finish. I wonder why?

Even kit assemblers with these aluminum pre punched kits take years. Many scratch built steel airplanes take years also but many many are done in a matter of months, so it's irrelevant. I've read about Thorp builders scratch building them in under 6 months.

In the old days they didn't have distractions I suppose. Things like the Internet, mobile devices etc. People watched less tv I'd imagine. There's probably a lesson in here somewhere.
How many of them were empty-nesters or retirees with no kids at home, and were either single or had an expectation that their wife handled all of the household tasks? I could build an airplane a lot faster if I were free to work on it 8-10 hours a day, 7 days a week, and didn't have to do things like go to work, take care of my son, bring my wife everywhere she needs to go, etc.
 

Hot Wings

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I could build an airplane a lot faster if I were free to work on it 8-10 hours a day, 7 days a week, and didn't have to do things like go to work, take care of my son, bring my wife everywhere she needs to go, etc.
I've been in both situations. Way back in time I averaged 5 hours a night and 15 hours on weekends working on the BD-5. I was single working 9 to 5 for wages and the -5 was taking up the garage. Running a business and a family (that thinks garages are for cars :shock:) sucks time.
 

Little Scrapper

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How many of them were empty-nesters or retirees with no kids at home, and were either single or had an expectation that their wife handled all of the household tasks? I could build an airplane a lot faster if I were free to work on it 8-10 hours a day, 7 days a week, and didn't have to do things like go to work, take care of my son, bring my wife everywhere she needs to go, etc.
That's my point. For myself, I run a viable business, married, 3 kids who are active etc etc. I'm a very fast fabricator but unfortunately I only have so much time.

Regardless of materials and methods to build it still takes over a thousand hours for most airplanes. So 10 hours a week is 520 hours a year! 10 hours a week, for me at least, is a lot of time to find. I suspect others have the same issue.
 
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